HUMAN GENOME SCIENCES INC
8-K, 1998-05-28
IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES
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                       SECURITIES AND EXCHANGE COMMISSION

                              WASHINGTON, DC 20549

                             _______________________

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


 Date of Report (Date of earliest event reported): May 28, 1998 (May 20, 1998)



                           HUMAN GENOME SCIENCES, INC.

               (Exact Name of Registrant as Specified in Charter)





                                    Delaware
                         (State or Other Jurisdiction of
                                 Incorporation)

                                    0-022962
                            (Commission File Number)


                                   22-3178468
                       (IRS Employer Identification No.)


              9410 Key West Avenue, Rockville, Maryland 20850-3338
               (Address of Principal Executive Offices) (ZIP Code)





       Registrant's telephone number, including area code: (301) 309-8504



          (Former Name or Former Address, if Changed Since Last Report)





<PAGE>

Item 5.       Other Events.

     On May 20, 1998,  Human Genome  Sciences,  Inc. (the  "Company")  adopted a
Shareholder  Rights Plan which  provided  for the  issuance of  preferred  share
purchase rights.
 
     In order  to  implement  the new  Shareholder  Rights  Plan,  the  Board of
Directors of the Company has  authorized a distribution  of one preferred  share
purchase right (a "Right") for each outstanding share of common stock, par value
$.01 (the "Common Shares"),  of the Company. The dividend is payable on June 26,
1998 to stockholders of record on May 27, 1998 (the "Record Date"). The terms of
the Rights are set forth in a Rights Agreement (the "Rights  Agreement") between
the Company and American Stock  Transfer & Trust  Company,  as Rights Agent (the
"Rights Agent"), dated as of May 20, 1998, as amended from time to time.

     Each Right entitles the registered  holder to purchase from the Company one
one-thousandth  of a share of Junior  Participating  Preferred  Stock, par value
$.01,  of the  Company  (the  "Preferred  Shares") at a price of $250.00 per one
one-thousandth  of  a  Preferred  Share  (the  "Purchase  Price"),   subject  to
adjustment.

     Until the earlier to occur of (i) 10 days  following a public  announcement
that  an  "Acquiring  Person"  acquired,  or  obtained  the  right  to  acquire,
beneficial  ownership of 15% (20% in the case of the Bass  Investors (as defined
below)) or more of the  outstanding  Common  Shares or (ii) 10 business days (or
such later date as may be  determined  by the Board of  Directors  prior to such
time as any person becomes an Acquiring  Person)  following the  commencement or
announcement  of an  intention  to make a tender  offer or  exchange  offer  the
consummation  of which  would  result in the  "Acquiring  Person"  becoming  the
beneficial  owner of 15% (20% in the case of the Bass Investors) or more of such
outstanding   Common  Shares  (the  earlier  of  such  dates  being  called  the
"Distribution  Date"), the Rights will be evidenced,  with respect to any of the
Common Share  certificates  outstanding  as of the Record  Date,  by such Common
Share  certificate.  Acquiring  Person  is  defined  as any  person  or group of
affiliated  or  associated  persons,  other than  employee  benefit plans of the
Company and its subsidiaries,  who has acquired beneficial ownership of 15% (20%
in the case of the Bass Investors) or more of the outstanding Common Shares. The
Rights Agreement  provides that, until the Distribution Date, the Rights will be
transferred with and only with the Common Shares.  Until the  Distribution  Date
(or  earlier  redemption  or  expiration  of  the  Rights),   new  Common  Share
certificates  issued after the Record Date upon  transfer or new issuance of the
Common  Shares will  contain a notation  incorporating  the Rights  Agreement by
reference.  Until the Distribution Date (or earlier  redemption or expiration of
the Rights),  the surrender for transfer of any  certificates  for Common Shares
outstanding  as of the Record  Date,  even  without  such  notation or a summary
description  of the Rights being  attached  thereto,  will also  constitute  the
transfer of the Rights  associated  with the Common Shares  represented  by such
certificate.  As soon as practicable  following the Distribution Date,  separate
certificates  evidencing  the Rights  ("Right  Certificates")  will be mailed to
holders  of record of the  Common  Shares  as of the  close of  business  on the
Distribution Date and such separate Right  Certificates  alone will evidence the
Rights.  The Bass  Investors  consist  of Sid R. Bass and  certain  stockholders
affiliated with him.

                                      -2-


<PAGE>

     The Rights are not exercisable until the Distribution Date. The Rights will
expire on May 20,  2008,  unless  earlier  redeemed by the Company as  described
below.

     The  Purchase  Price  payable,  and the  number of  Common  Shares or other
securities  or  property  issuable,  upon  exercise of the Rights are subject to
adjustment  from time to time to  prevent  dilution  (i) in the event of a stock
dividend on, or a  subdivision,  combination or  reclassification  of the Common
Shares, (ii) upon the grant to holders of the Common Shares of certain rights or
warrants to subscribe for Common Shares or  convertible  securities at less than
the current market price of the Common Shares or (iii) upon the  distribution to
holders of the Common Shares of evidences of indebtedness  or assets  (excluding
regular  periodic  cash  dividends  out of  earnings  or  retained  earnings  or
dividends  payable in Preferred  Shares) or of  subscription  rights or warrants
(other than those referred to above).

     With  certain  exceptions,  no  adjustment  in the  Purchase  Price will be
required until  cumulative  adjustments  require an adjustment of at least 1% in
such Purchase Price. No fractional  Preferred  Shares (other than fractions that
are  integral  multiples  of one  one-thousandth  of a Preferred  Share) will be
issued and in lieu  thereof,  a payment in cash will be made based on the market
price  of the  Common  Shares  on the  last  trading  date  prior to the date of
exercise.

     In the event that the Company were  acquired in a merger or other  business
combination  transaction  or 50% or more of its  consolidated  assets or earning
power were sold,  proper  provision  will be made so that each holder of a Right
shall  thereafter  have the right to receive,  upon the exercise  thereof at the
then current exercise price of the Right,  that number of shares of common stock
of the  acquiring  company  which at the time of such  transaction  would have a
market value of two times the exercise price of the Right. In the event that the
Company were the  surviving  corporation  in a merger and the Common Shares were
not changed or exchanged, or in the event that any person becomes the beneficial
owner of 15% (20% in the case of the Bass  Investors)  or more of the  Company's
Common  Shares  and  hence an  Acquiring  Person  (a  "Flip-In  Event"),  proper
provision  will be made so that each  holder of a Right,  other than Rights that
are or were beneficially owned by the Acquiring Person (which will thereafter be
void),  will  thereafter  have the right to receive upon exercise that number of
Common Shares having a market value of two times the exercise price of the Right
(or Preferred Shares if so elected by the Board of Directors).

     At any time prior to the close of business on the date a person  becomes an
Acquiring Person, the Company,  by a vote of the Board of Directors,  may redeem
the  Rights  in  whole,  but not in part,  at a price of $.001  per  Right  (the
"Redemption  Price").  The  right of  redemption  also may be  reinstated  under
certain  circumstances  described in the Rights Agreement,  including if a term,
provision, covenant or restriction of the Rights Agreement is held by a court or
other  authority  to be invalid,  void or  unenforceable.  Immediately  upon the
action of the Board of Directors ordering redemption of the Rights, the right to
exercise the Rights will  terminate  and the only right of the holders of Rights
will be to receive the Redemption Price.


                                      -3-
<PAGE>

     At any time after any  person  becomes an  Acquiring  Person,  the Board of
Directors  of the Company  may, at its option,  exchange all or part of the then
outstanding and exercisable Rights (excluding Rights of an Acquiring Person that
have become void) for Common Shares at an exchange ratio of one Common Share per
Right,  appropriately  adjusted to reflect any stock  split,  stock  dividend or
similar  transaction  occurring  after  the  date  hereof.  Notwithstanding  the
foregoing, the Board of Directors shall not be empowered to effect such exchange
at any time  after  any  Acquiring  Person,  together  with all  Affiliates  and
Associates of such Person,  becomes the  Beneficial  Owner of 50% or more of the
Common Shares then outstanding. In lieu of Common Shares, the Board of Directors
may elect to substitute Preferred Shares for any such exchange.

     Until a Right is  exercised,  the  holder  thereof,  as such,  will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive  dividends.  While the distribution of the Rights will not
be taxable to stockholders or to the Company,  stockholders may,  depending upon
the circumstances,  recognize taxable income in the event that the Rights become
exercisable  for Common  Stock (or other  consideration)  of the  Company or for
common stock of the acquiring company as set forth above.

     Other than an amendment to those  provisions  relating to certain  economic
terms of the  Rights,  any of the  provisions  of the  Rights  Agreement  may be
amended by the Board of Directors of the Company prior to the Distribution Date,
including,   without  limitation,  any  amendment  deemed  to  be  necessary  or
appropriate in light of any judicial or other legal developments, whether or not
binding  precedent in respect of the Rights  Agreement.  After the  Distribution
Date,  the  provisions  of the Rights  Agreement  may be amended by the Board in
order to cure any ambiguity,  to make changes which do not adversely  affect the
interest of holders of Rights (excluding the interests of any Acquiring Person),
or to shorten or lengthen any time period under the Rights Agreement;  provided,
however,  that no amendment to adjust the time period governing redemption shall
be made at such time as the Rights are not  redeemable  and no amendment  may be
made after the Distribution Date which shortens the final expiration date of the
Rights Agreement.  Without limiting any of the foregoing, at any time prior to a
Person (other than certain  employee  benefit plans of the Company)  becoming an
Acquiring  Person,  the  Board  may  amend  the  Rights  Agreement  to lower the
threshold  for  exercisability  of the  Rights  (and  the  determination  of the
existence  of an  Acquiring  Person)  from  15%  (20% in the  case  of the  Bass
Investors)  to any  percentage  greater  than  the  greater  of (i) the  largest
percentage  of  outstanding  Common  Shares  then  known  to the  Company  to be
beneficially  owned by any Person or group of affiliated  or associated  persons
(subject to certain  exceptions as set forth in the Rights  Agreement)  and (ii)
10%.






                                      -4-
   

<PAGE>

     A copy of the  Rights  Agreement  is being  filed with the  Securities  and
Exchange  Commission as an Exhibit  hereto and is available  free of charge from
the  Company.  This  summary  description  of the Rights  does not purport to be
complete and is qualified in its entirety by reference to the Rights  Agreement,
as amended from time to time, which is hereby incorporated herein by reference.

Item 7.      Financial Statements, Pro Forma Financial Information and Exhibits.

(a) and (b)   Financial Statements and Pro Forma Information.   None.

(c)  Exhibits.  The  following  exhibits  are filed  with this  report,  and the
foregoing description is modified by
reference to such exhibits:

               4.   Rights  Agreement  between the Company  and  American  Stock
                    Transfer & Trust Company,  as Rights Agent,  dated as of May
                    20,  1998  which  includes  as  Exhibit  A the Form of Right
                    Certificate.   Pursuant  to  the  Rights  Agreement,   Right
                    Certificates will not be mailed until as soon as practicable
                    after the  earlier of the tenth day  following  announcement
                    that a person or group has acquired beneficial  ownership of
                    15% (20% in the case of the Bass  Investors)  or more of the
                    Common  Shares  or the  tenth  business  day  after a person
                    commences  or announces  its  intention to commence an offer
                    the   consummation   of  which  would  result  in  a  person
                    beneficially  owning  15%  (20%  in the  case  of  the  Bass
                    Investors) or more of the Common Shares. 















                                      -5-

<PAGE>

                                   SIGNATURES

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                                         HUMAN GENOME SCIENCES, INC.



                                         By: /s/ Steven C. Mayer              
                                             ------------------------


Date:  May 28, 1998





















                                      -6-
<PAGE>

                                  EXHIBIT INDEX


Exhibit              Description                                     Page No.
- -------              -----------                                     --------

   4.      Rights Agreement between the Company and American Stock      9
           Transfer  & Trust  Company,  dated  as of May 20,  1998
           which   includes   as  Exhibit  A  the  Form  of  Right
           Certificate.  Pursuant to the Rights  Agreement,  Right
           Certificates  will  not be  mailed  until  as  soon  as
           practicable after the earlier of the tenth business day
           following  announcement  that a  person  or  group  has
           acquired  beneficial  ownership of 15% (20% in the case
           of the Bass  Investors) or more of the Common Shares or
           the  tenth  business  day after a person  commences  or
           announces  its  intention  to  commence  an  offer  the
           consummation   of  which  would   result  in  a  person
           beneficially  owning  15%  (20% in the case of the Bass
           Investors) or more of the Common Shares.














                                      -7-








<PAGE>





                           HUMAN GENOME SCIENCES, INC.


                                       and


                     AMERICAN STOCK TRANSFER & TRUST COMPANY


                                  Rights Agent



                                Rights Agreement

                            Dated as of May 20, 1998


<PAGE>

                                                       


                                TABLE OF CONTENTS
                                                                           Page

Section 1.     Certain Definitions.......................................    1

Section 2.     Appointment of Rights Agent ..............................    6

Section 3.     Issue of Right Certificates...............................    6

Section 4.     Form of Right Certificates................................    9

Section 5.     Countersignature and Registration.........................    9

Section 6.     Transfer, Split Up, Combination and
                  Exchange of Right Certificates;
                  Mutilated, Destroyed, Lost or
                  Stolen Right Certificates..............................   10

Section 7.     Exercise of Rights; Purchase Price;
                  Expiration Date of Rights; Nullification of Rights.....   11

Section 8.     Cancellation and Destruction of Rights Certificates.......   15

Section 9.     Reservation and Availability of Preferred Shares..........   15

Section 10.     Preferred Shares Record Date.............................   17

Section 11.    Adjustment of Purchase Price,
                  Number of Shares or Number of Rights...................   17

Section 12.    Certificate of Adjusted Purchase
                  Price or Number of Shares..............................   28

Section 13.    Consolidation, Merger or Sale or Transfer of
                  Assets or Earning Power................................   28

Section 14.    Fractional Rights and Fractional Shares...................   34

Section 15.    Rights of Action..........................................   36

Section 16.    Agreement of Right Holders................................   36



                                      -i-



<PAGE>

Section 17.    Right Certificate Holder Not Deemed a Stockholder.........   37

Section 18.    Concerning the Rights Agent...............................   37

Section 19.    Merger or Consolidation or Change of
                  Name of Rights Agent...................................   38

Section 20.    Duties of Rights Agent....................................   39

Section 21.    Change of Rights Agent....................................   42

Section 22.    Issuance of New Right Certificates........................   43

Section 23.    Redemption................................................   44

Section 24.    Notice of Certain Events..................................   45

Section 25.    Notices...................................................   46

Section 26.    Supplements and Amendments................................   47

Section 27.    Exchange..................................................   48

Section 28.    Successors................................................   50

Section 29.    Determinations and Actions by the Board of Directors, etc.   50

Section 30.    Benefits of this Agreement................................   51

Section 31.    Severability..............................................   51

Section 32.    Governing Law.............................................   51

Section 33.    Counterparts..............................................   51

Section 34.    Descriptive Headings......................................   52

Exhibit A  --  Certificate  of  Designation of  Series  A  Junior  Participating
               Preferred Stock

Exhibit B  --  Form of Right Certificate

Exhibit C  --  Summary of Rights to Purchase Preferred Shares


                                      -ii-

<PAGE>

                                 RIGHT AGREEMENT

     This Agreement, dated as of May 20, 1998, to be immediately effective as of
the Effective  Date (as  hereinafter  defined),  between Human Genome  Sciences,
Inc., a Delaware  corporation  (the  "Company"),  and American  Stock Transfer &
Trust Company, a New York corporation (the "Rights Agent").

                              W I T N E S S E T H:

     WHEREAS,  the Board of Directors of the Company has authorized and declared
a dividend of one preferred  share  purchase right (a "Right") for each share of
Common  Stock,  par  value  $.01 per  share,  of the  Company  ("Common  Share")
outstanding  at the close of  business  on the  Effective  Date (as  hereinafter
defined), each Right representing the right to purchase one one-thousandth share
of Junior  Participating  Preferred  Stock,  par value  $0.01 per share,  of the
Company  having the  rights  and  preferences  set forth in the  Certificate  of
Designation  filed with the  Secretary  of State of the State of Delaware on May
26, 1998 upon the terms and subject to the conditions  herein set forth, and has
further  authorized  the issuance of one Right with respect to each Common Share
that shall become outstanding between the Effective Date and the earliest of the
Distribution  Date, the Redemption  Date and the Final  Expiration Date (as such
terms are defined in Sections 3 and 7 hereof).

     Accordingly,  in  consideration  of the premises and the mutual  agreements
herein set forth, the parties agree as follows:

     Section  1.  Certain Definitions.  For  purposes  of  this  Agreement,  the
following terms have the meanings indicated:

     (a)  "Acquiring  Person" shall mean any Person (as such term is hereinafter
defined) who or which,  together with all  Affiliates  and  Associates  (as such
terms are hereinafter defined) of such Person, shall be the Beneficial Owner (as
such term is  hereinafter  defined)  of 15% or more of the  Common  Shares  then
outstanding,  but shall not  include  (i) the  Company,  any  Subsidiary  of the
Company or any employee  benefit plan of the Company or of any Subsidiary of the
Company, or any Person organized, appointed or established by the Company for or
pursuant to the terms of any such plan, or (ii) any Person who has become such a
Beneficial  Owner  solely  because  (A) of a  reduction  in the number of Common
Shares  outstanding  or (B) it acquired  such  Beneficial  Ownership in the good
faith belief that such acquisition would not (x) cause such Beneficial Ownership
to exceed 15% (20% in the case of the Bass Investors (as herein defined)) of the
Common Shares then outstanding and such Person relied in good faith in computing
the  percentage  of its  Beneficial  Ownership  on  publicly  filed  reports  or
documents of the Company which are  inaccurate or  out-of-date  or (y) otherwise
cause a Distribution Date or the adjustment provided for in Section 11(a)(ii) to
occur. Notwithstanding the foregoing, (i) the Bass Investors shall not be deemed
an Acquiring  Person unless the Bass Investors,  together with their  Affiliates
and Associates, become the Beneficial Owner of more than 20% of the Common Stock
then  outstanding and (ii) if any Person that is not an Acquiring  Person due to

                                      -1-
<PAGE>

clause (ii) of the prior  sentence does not reduce its  percentage of Beneficial
Ownership  of  Common  Shares  to less  than  15%  (20% in the  case of the Bass
Investors) by the Close of Business on the fifth  Business Day after notice from
the  Company  (the date of  notice  being  the  first  day)  that such  Person's
Beneficial  Ownership  of Common  Shares so exceeds  15% (20% in the case of the
Bass  Investors) such Person shall, at the end of such five Business Day period,
become an  Acquiring  Person (and such clause (ii) shall no longer apply to such
Person). For purposes of this definition,  the determination  whether any Person
acted in "good faith" shall be conclusively determined by the Board of Directors
of the  Company.

     (b) "Affiliate" and "Associate" shall have the respective meanings ascribed
to such  terms in Rule  12b-2 of the  General  Rules and  Regulations  under the
Securities  Exchange Act of 1934, as amended (the "Exchange  Act"), as in effect
on the date of this Agreement.

     (c) "Bass Investors" shall mean each of Alexandra D. Sterling 1990 Trust A,
Annie R. Bass Grandson's  Trust for Lee M. Bass,  Annie R. Bass Grandson's Trust
for Sid R. Bass,  Bass Sid R Management  Trust,  Cotham Family  Partners,  L.P.,
Hyatt Anne Bass Successor  Trust,  Lee Caroline Hallman 1992 Trust, Lee M. Bass,
Lisa D. Sterling 1990 Trust,  Mary Susanna Hallman 1992 Trust,  Matthew Kingston
Cotham 1996 Trust,  Nancy L. Bass, P. Andrew  Sterling 1990 Trust,  Panther City
Investment  Company,  Panther City Production  Company,  Perry R. Bass, Perry R.
Bass, II 1993 A Trust,  Peter Sterling,  Philip D. Sterling 1990 Trust A, Ramona
Frates Bass 1993 A Trust,  Samantha Sims Bass Successor  Trust, Sid R. Bass, Sid
R.  Bass  Management  Trust,  Sophie  Seeligson  Bass  1993 A  Trust,  The  Bass
Management  Trust, W. Robert Cotham,  Wesley Guylay Capital  Management,  Wesley
Richard Guylay,  William P. Hallman, III 1992 Trust and William P. Hallman, Jr.;
provided, however, that the Beneficial Ownership of Common Shares by each of the
foregoing  shall  be  aggregated  together  with  that  of  any  Affiliates  and
Associates thereof to determine the Bass Investors' Beneficial Ownership for the
purposes of determining  whether the Bass Investors are an Acquiring Person.

     (d) A Person shall be deemed the "Beneficial  Owner" of and shall be deemed
to  "beneficially  own" any  securities:  (i) which  such  Person or any of such
Person's  Affiliates or Associates is deemed to  beneficially  own,  directly or
indirectly,  within  the  meaning  of  Rule  13d-3  of  the  General  Rules  and
Regulations  under the Exchange Act, as in effect on the date of this Agreement;
(ii) which such Person or any of such Person's  Affiliates or Associates has (A)
the right to acquire  (whether  such right is  exercisable  immediately  or only
after  the  passage  of  time)  pursuant  to  any   agreement,   arrangement  or
understanding  (whether  or not in writing and other than  customary  agreements
with and between  underwriters  and selling group members with respect to a bona
fide public offering of securities),  or upon the exercise of conversion rights,
exchange  rights,  rights  (other than the  Rights),  warrants  or  options,  or
otherwise,  provided,  however, that a Person shall not be deemed the Beneficial
Owner of, or to beneficially  own,  securities  tendered pursuant to a tender or
exchange offer made pursuant to and in accordance with the applicable  rules and
regulations  promulgated  under  the  Exchange  Act made by or on behalf of such
Person or any of such  Person's  Affiliates  or  Associates  until such tendered
securities  are accepted  for  purchase;  or (B) the right to vote,  alone or in
concert with others,  pursuant to any agreement,  arrangement  or  understanding
(whether  or not in  writing),  provided,  however,  that a Person  shall not be
deemed the  Beneficial  Owner of, or to  beneficially  own,  any security if the
agreement,  arrangement or understanding to vote such security (1) arises solely
from a revocable proxy or consent given in response to a

                                      -2-
<PAGE>

public proxy or consent  solicitation  made pursuant to, and in accordance with,
the  applicable  rules  and  regulations  of the  Exchange  Act  and  (2) is not
reportable  by such Person on a Schedule  13D report  under the Exchange Act (or
any  comparable or successor  report);  or (iii) which are  beneficially  owned,
directly  or  indirectly,  by any other  Person with which such Person or any of
such  Person's  Affiliates  or  Associates  has any  agreement,  arrangement  or
understanding  (whether  or not in writing and other than  customary  agreements
with and between  underwriters  and selling group members with respect to a bona
fide public  offering of  securities),  for the purpose of  acquiring,  holding,
voting (except  pursuant to a revocable  proxy or consent as described in clause
(B) of  subparagraph  (ii) of this paragraph (d)) or disposing of any securities
of the  Company.  Notwithstanding  anything  in this  definition  of  Beneficial
Ownership to the  contrary,  (A) the phrase "then  outstanding,"  when used with
reference to a Person's Beneficial Ownership of securities of the Company, shall
mean the number of such securities then issued and outstanding together with the
number of such securities not then actually  issued and  outstanding  which such
Person would be deemed to own beneficially hereunder and (B) a Person engaged in
business as an  underwriter  of  securities  shall not be  considered  to be the
"Beneficial Owner" of or to "beneficially  own" any securities  acquired through
such  Person's  participation  in good faith in a firm  commitment  underwriting
until the expiration of forty (40) days after the date of such acquisition.  (d)
"Business  Day" shall mean any day other than a  Saturday,  Sunday,  or a day on
which banking  institutions in the States of New York or Maryland are authorized
or obligated by law or executive order to close.

     (e) "Close of  Business"  on any given date shall mean 5:00 P.M.,  New York
City time, on such date; provided,  however, that if such date is not a Business
Day it shall mean 5:00 P.M., New York City time, on the next succeeding Business
Day.

     (f) "Common  Shares"  when used with  reference  to the Company  shall mean
shares of Common  Stock,  par value  $.01 per  share,  of the  Company.  "Common
Shares" when used with reference to any Person other than the Company shall mean
the capital stock (or, in the case of any unincorporated  entity, the equivalent
equity  interest)  with the  greatest  voting  power of such  Person or, if such
Person is a Subsidiary of another Person, the Person or Persons which ultimately
control such  first-mentioned  Person.

     (g)  "Distribution  Date"  shall  have the  meaning  set forth in Section 3
hereof.

     (h) "Effective Date" shall mean June 20, 1998.

     (i) "Final  Expiration  Date" shall have the meaning set forth in Section 7
hereof.

     (j) "Person" shall mean any  individual,  firm,  corporation,  partnership,
limited liability company,  association,  trust,  unincorporated organization or
other  entity,  and shall include any successor (by merger or otherwise) of such
entity.

     
                                      -3-
<PAGE>

     (k) "Preferred Shares" shall mean shares of Junior Participating  Preferred
Stock, $0.01 par value, of the Company.

     (l) "Purchase  Price" shall have the meaning set forth in Section 4 hereof.

     (m) "Redemption Date" shall have the meaning set forth in Section 7 hereof.

     (n) "Securities Act" shall mean the Securities Act of 1933, as amended.


     (o)  "Share   Acquisition  Date"  shall  mean  the  first  date  of  public
announcement  (which,  for purposes of this definition,  shall include,  without
limitation,  a report filed pursuant to Section 13(d) under the Exchange Act) by
the Company or an Acquiring  Person that an Acquiring  Person has become such or
such earlier date as a majority of the Board of Directors  shall become aware of
the  existence  of  an  Acquiring  Person;  provided,  however,  that  no  Share
Acquisition  Date shall be deemed to have occurred on such date if,  pursuant to
the  definition of "Acquiring  Person," a Person is deemed  (whether prior to or
after the date that would  otherwise be a Share  Acquisition  Date) not to be or
have become an Acquiring  Person.

     (p)  "Subsidiary"  of any Person shall mean any corporation or other entity
of which a majority  of the  voting  power of the voting  equity  securities  or
equity interests is owned, directly or indirectly, by such Person.

     (q)  "Triggering  Event"  shall  mean any  action  which  would  cause  the
occurrence of any event described in Section  11(a)(ii) or Section 13(a) hereof.

     Section 2.  Appointmen of Rights  Agent.  The Company  hereby  appoints the
Rights  Agent to act as agent for the Company in  accordance  with the terms and
conditions  hereof,  and the Rights Agent hereby accepts such  appointment.  The
Company  may from  time to time  appoint  such  Co-Rights  Agents as it may deem
necessary  or  desirable  (the term  "Rights  Agent" being used herein to refer,
collectively,  to the Rights Agent together with any such Co-Rights Agents).  In
the event the Company  appoints one or more  Co-Rights  Agents,  the  respective
duties of the Rights  Agent and any  Co-Rights  Agents  shall be as the  Company
shall determine.

     Section 3. Issue of Right  Certificates.  (a) Until the  earlier of (i) the
tenth day after the Share  Acquisition  Date or (ii) the tenth  Business Day (or
such later date as may be determined  by action of the Board of Directors  prior
to such time as any Person  becomes an Acquiring  Person)  after the date of the
commencement of, or first public  announcement of the intention of any Person to
commence,  a tender or exchange offer the  consummation of which would result in
beneficial  ownership by a Person,  together with its  Affiliates and Associates
(other than the Company,  any Subsidiary of the Company or any employee  benefit
plan of the Company or of any  Subsidiary  of the Company or any Person  holding
Common Shares for or pursuant to the terms of any such plan) of 15% or more (20%

                                      -4-

<PAGE>
or more in the case of the Bass Investors) of the Common Shares then outstanding
(including  any such date that is after the date of this  Agreement and prior to
the issuance of the Rights; the earlier of the dates in subsections (i) and (ii)
hereof being herein referred to as the "Distribution  Date"), the Rights will be
evidenced  (subject to the provisions of paragraph (b) of this Section 3) by the
certificates  for Common  Shares  registered  in the names of the holders of the
Common Shares (which  certificates for the Common Shares shall also be deemed to
be Right Certificates) and not by separate Right Certificates,  and the right to
receive Right  Certificates  will be  transferable  only in connection  with the
transfer of Common Shares. As soon as practicable  after the Distribution  Date,
the Rights Agent will send, by  first-class,  insured,  postage prepaid mail, to
each  record  holder  of  Common  Shares  as of the  close  of  business  on the
Distribution  Date,  at the address of such  holder  shown on the records of the
Company,  a Right  Certificate,  in substantially  the form of Exhibit A hereto,
evidencing one Right for each Common Share so held. As of the Distribution Date,
the  Rights  will be  evidenced  solely  by the Right  Certificates.

     (b) On the Effective Date or as soon as practicable thereafter, the Company
will  send a copy of a  Summary  of  Rights to  Purchase  Preferred  Shares,  in
substantially  the form attached  hereto as Exhibit B (the "Summary of Rights"),
by first-class,  postage prepaid mail, to each record holder of Common Shares as
of the Close of Business  on the  Effective  Date,  at the address of the record
holder shown on the records of the Company.  With  respect to  certificates  for
Common Shares outstanding as of the Effective Date, until the Distribution Date,
the Rights will be evidenced by the certificates for Common Shares registered in
the  names  of the  holders  thereof  (together  with a copy of the  Summary  of
Rights).  Until the Distribution  Date (or the earlier of the Redemption Date or
Final Expiration Date), the surrender for transfer of any certificate for Common
Shares  outstanding on the Effective Date, with or without a copy of the Summary
of Rights  attached  thereto,  shall also  constitute the transfer of the Rights
associated with the Common Shares  represented  thereby.  (c)  Certificates  for
Common Shares  issued after the Effective  Date but prior to the earliest of the
Distribution  Date, the Redemption Date and the Final Expiration Date shall have
impressed on, printed on, written on or otherwise  affixed to them the following
legend:

        This certificate also evidences and entitles the holder hereof to
             certain  rights as set forth in a Rights  Agreement  between
             Human Genome  Sciences,  Inc. and American  Stock Transfer &
             Trust  Company,  dated as of May 20,  1998,  as amended from
             time to time (the  "Rights  Agreement"),  the terms of which
             are hereby  incorporated  herein by reference  and a copy of
             which is on file at the principal executive offices of Human
             Genome Sciences,  Inc. Under certain  circumstances,  as set
             forth in the Rights Agreement,  the Rights will be evidenced
             by separate  certificates and will no longer be evidenced by
             this certificate.  Human Genome Sciences,  Inc. will mail to
             the  holder  of  this  certificate  a  copy  of  the  Rights
             Agreement,  as in  effect  on the date of  mailing,  without
             charge promptly after receipt of a written request therefor.
             Rights owned by or  transferred to any person who becomes an
             Acquiring  Person or their Affiliates or Associates (as such
             terms are  defined  in the  Rights  Agreement)  and  certain
             transferees  thereof  will  become null and void and will no
             longer be transferable.


                                      -5-
<PAGE>
With respect to the  certificates  containing  the foregoing  legend,  until the
Distribution  Date, the Rights associated with the Common Shares  represented by
such  certificates  shall  be  evidenced  by such  certificates  alone,  and the
surrender  for  transfer  of any such  certificate  shall  also  constitute  the
transfer of the Rights  associated  with the Common Shares  represented  by such
certificate.  In the event that the Company purchases or otherwise  acquires any
Common Shares after the Effective Date but prior to the  Distribution  Date, any
Rights  associated  with such Common Shares shall be deemed canceled and retired
so that the Company shall not be entitled to exercise any Rights associated with
the  Common  Shares  which  are  no  longer  outstanding.  Notwithstanding  this
paragraph (c), the omission of a legend shall not affect the  enforceability  of
any part of this Agreement or the rights of any holder of the Rights.

     Section  4. Form of Right  Certificates.  The Right  Certificates  (and the
forms of election to purchase  Preferred  Shares and of assignment to be printed
on the reverse thereof) shall be substantially  the same as Exhibit A hereto and
may have such marks of identification  or designation and legends,  summaries or
endorsements  printed thereon as the Company may deem appropriate and as are not
inconsistent  with the  provisions of this  Agreement,  or as may be required to
comply with any  applicable  law or with any rule or  regulation  made  pursuant
thereto  or with any rule or  regulation  of any  stock  exchange  or  automated
quotation  system on which the  Rights  may from time to time be  listed,  or to
conform to usage.  Subject to the  provisions of Sections 11 and 22 hereof,  the
Right Certificates,  shall entitle the holders thereof to purchase the number of
Preferred   Shares  as  shall  be  set  forth  therein  at  the  price  per  one
one-thousandth  of a Preferred  Share set forth therein (the "Purchase  Price"),
but the number of such Preferred  Shares and the Purchase Price shall be subject
to adjustment as provided herein.

     Section 5. Countersignature and Registration.  The Right Certificates shall
be executed on behalf of the Company by its Chairman of the Board, its President
or any Vice President, either manually or by facsimile signature, and shall have
affixed  thereto  the  Company's  seal or a  facsimile  thereof  which  shall be
attested by the  Secretary  or an Assistant  Secretary  of the  Company,  either
manually or by facsimile  signature.  Each Right  Certificate  shall be manually
countersigned  by an authorized  signatory of the Rights Agent, but it shall not
be necessary for the same signatory to countersign all of the Right Certificates
issued hereunder.  No Right Certificate shall be valid for any purpose unless so
countersigned.  In case any  officer of the  Company  who shall have  signed any
Right   Certificate  shall  cease  to  be  an  officer  of  the  Company  before
countersignature   by  the  Rights  Agent  and  issuance  and  delivery  of  the
certificate  by  the  Company,  such  Right  Certificate,  nevertheless,  may be
countersigned  by the Rights Agent and issued and  delivered by the Company with
the same force and effect as though the person who signed such Right Certificate
had not ceased to be an officer of the  Company.  Any Right  Certificate  may be
signed on behalf of the Company by any person who, on the date of the  execution
of the Right  Certificate,  shall be a proper officer of the Company to sign the
Right  Certificate,  although  at the  date  of the  execution  of  this  Rights
Agreement that person was not an officer.

     Following the Distribution  Date, the Rights Agent will keep or cause to be
kept, at its principal office,  books for registration and transfer of the Right
Certificates issued hereunder.  Such books shall show the names and addresses of
the respective holders of the Right Certificates, the number of Rights evidenced
on its face by each of the  Right  Certificates  and the  date  and  certificate
number of each of the Right Certificates.


                                      -6-

<PAGE>
     Section  6.  Transfer,   Split  Up,   Combination  and  Exchange  of  Right
Certificates;  Mutilated, Destroyed, Lost or Stolen Right Certificates.  Subject
to the provisions of Section 14 hereof,  at any time after the Close of Business
on the  Distribution  Date,  and at or prior to the  Close  of  Business  on the
earlier  of the  Redemption  Date  or  the  Final  Expiration  Date,  any  Right
Certificate or Certificates  (other than Right Certificates  representing Rights
that have become void  pursuant to Sections  7(g) and  11(a)(ii)  hereof or that
have been exchanged pursuant to Section 27 hereof) may be transferred, split up,
combined or exchanged for another Right  Certificate or Certificates,  entitling
the registered holder to purchase a like number of Preferred Shares as the Right
Certificate or Certificates  surrendered  then entitled such holder to purchase.
Any registered  holder  desiring to transfer,  split up, combine or exchange any
Right  Certificate or Certificates  shall make a request in writing delivered to
the Rights Agent,  and shall surrender the Right  Certificate or Certificates to
be transferred,  split up, combined or exchanged at the principal  office of the
Rights  Agent  designated  for such  purpose.  Neither the Rights  Agent nor the
Company  shall be  obligated to take any action  whatsoever  with respect to the
transfer of any surrendered  Right Certificate until the registered holder shall
have completed and signed the certificate contained in the form of assignment on
the reverse side of the Right  Certificate  and shall have  provided  additional
evidence of the identity of the Beneficial Owner (or former Beneficial Owner) or
Affiliates  or  Associates  thereof as the  Company  shall  reasonably  request.
Thereupon the Rights Agent shall  countersign and deliver to the person entitled
thereto a Right  Certificate  or Right  Certificates,  as the case may be, as so
requested.   The  Company  may  require   payment  from  the  holders  of  Right
Certificates  of a sum sufficient to cover any tax or  governmental  charge that
may be  imposed  in  connection  with any  transfer,  split up,  combination  or
exchange of Right Certificates.  Subject to the provisions of Section 11(a)(ii),
upon  receipt  by the  Company  and the  Rights  Agent  of  evidence  reasonably
satisfactory  to them of the loss,  theft,  destruction or mutilation of a Right
Certificate,  and,  in case of  loss,  theft or  destruction,  of  indemnity  or
security  reasonably  satisfactory  to them and, at the request of the  Company,
reimbursement  to the Company and the Rights  Agent of all  reasonable  expenses
incidental thereto, and upon surrender to the Rights Agent and cancellation of a
Right Certificate if mutilated, the Company will execute and deliver a new Right
Certificate of like tenor to the Rights Agent for  countersignature and delivery
to the  registered  owner in lieu of the  Right  Certificate  so  lost,  stolen,
destroyed or mutilated. 

     Notwithstanding  any other  provision  hereof,  the  Company and the Rights
Agent may amend this Rights  Agreement to provide for  uncertificated  Rights in
addition to or in place of Rights evidenced by Right Certificates.
 
     Section 7. Exercise of Rights;  Purchase Price;  Expiration Date of Rights;
Nullification  of Rights.  (a)  Subject to  Sections  7(f),  7(g) and  11(a)(ii)
hereof,  the registered  holder of any Right Certificate may exercise the Rights
evidenced  thereby (except as otherwise  provided herein) in whole or in part at
any time after the  Distribution  Date upon surrender of the Right  Certificate,
with the form of election to purchase on the reverse side thereof duly  executed
(with signatures duly  guaranteed),  to the Rights Agent at the principal office
of the Rights Agent in New York, New York, designated for such purpose, together
with payment of the Purchase  Price for each Common Share as to which the Rights
are  exercised,  at or prior to the earliest of (i) the Close of Business on the
tenth (10th)  anniversary of the Effective Date (the "Final  Expiration  Date"),
(ii) the time at which the Rights are  redeemed as provided in Section 23 hereof
(the "Redemption Date"), or (iii) the time at which such Rights are exchanged as
provided  in  Section  27  hereof.


                                      -7-
<PAGE>

     (b) The Purchase  Price for each one  one-thousandth  of a Preferred  Share
pursuant to the  exercise of a Right shall  initially  be $250.00.  The Purchase
Price and the number of Preferred Shares to be acquired upon exercise of a Right
shall be subject to adjustment  from time to time as provided in Sections 11 and
13 hereof.  The  Purchase  Price shall be payable in lawful  money of the United
States of America in accordance with paragraph (c) below.

     (c)  Except  as  otherwise  provided  herein,   upon  receipt  of  a  Right
Certificate  representing  exercisable  Rights,  with  the form of  election  to
purchase set forth on the reverse thereof duly executed,  accompanied by payment
of the Purchase Price for the number of one one-thousandths of a Preferred Share
to be purchased and an amount equal to any  applicable  transfer tax required to
be paid by the holder of such Right  Certificate  in  accordance  with Section 9
hereof in cash, or by certified  check or bank draft payable to the order of the
Company  and,  if  requested  by the  Company  or the  Rights  Agent  after  the
occurrence of any of the events described in  subparagraphs  (A), (B), or (C) of
Section  11(a)(ii)  hereof (which  request may be made before or after notice of
exercise of the Rights shall have been given), a representation and warranty, in
a form that the  Company  or the Rights  Agent may  reasonably  request,  by the
holder of Rights to be exercised  that the holder is not an Acquiring  Person or
an Affiliate  or  Associate of an Acquiring  Person and that the Rights were not
acquired,  directly or indirectly,  from an Acquiring  Person,  the Rights Agent
shall  thereupon  promptly (i) (A)  requisition  from any transfer  agent of the
Preferred  Shares  one or  more  certificates  representing  the  number  of one
one-thousandths  of a Preferred  Share to be  purchased  and the Company  hereby
irrevocably  authorizes its transfer agent to comply with all such requests,  or
(B) requisition from the depositary agent depositary receipts  representing such
number of one  one-thousandths  of a Preferred  Share as are to be purchased (in
which case  certificates for the Preferred  Shares  represented by such receipts
shall be  deposited  by the transfer  agent with the  depositary  agent) and the
Company hereby directs the  depositary  agent to comply with such request,  (ii)
when appropriate,  requisition from the Company the amount of cash to be paid in
lieu of issuance of fractional interests in shares in accordance with Section 14
hereof, (iii) promptly after receipt of such certificates,  cause the same to be
delivered  to or  upon  the  order  of  the  registered  holder  of  such  Right
Certificate, registered in such name or names as may be designated by the holder
and (iv) when appropriate, after receipt thereof, promptly deliver such cash, if
any, to or upon the order of the registered holder of the Right Certificate.

     (d) In case the registered  holder of any Right  Certificate shall exercise
less than all the Rights evidenced thereby,  a new Right Certificate  evidencing
Rights  equivalent to the Rights  remaining  unexercised  shall be issued by the
Rights Agent and delivered to the registered holder of such Right Certificate or
to his duly authorized assigns,  subject to the provisions of Section 14 hereof.

     (e) In the event that the Company is  obligated  to issue other  securities
(including  Common  Shares) of the  Company,  pay cash and/or  distribute  other
property   pursuant  to  Section  11(a)  hereof,   the  Company  will  make  all
arrangements necessary so that such other securities, cash and/or other property
are available for distribution by the Rights Agent, if and when appropriate.

                                      -8-

<PAGE>

     (f) Notwithstanding anything in this Agreement to the contrary, neither the
Rights Agent nor the Company  shall be  obligated  to undertake  any action with
respect to a registered holder upon the occurrence of any purported  exercise as
set  forth  in  this  Section  7  or  the  transfer  of  any  surrendered  Right
Certificates under Section 6, unless and until such registered holder shall have
(i)  completed  and  signed (A) in the case of a Section 7  exercise,  a form of
election or (B) in the case of a Section 6 transfer,  a form of  assignment,  as
set forth on the reverse side of the Right  Certificate,  and (ii) provided such
additional  evidence  of  the  identity  of  the  Beneficial  Owner  (or  former
Beneficial  Owner) or  Affiliates  or  Associates  thereof as the Company  shall
reasonably request.

     (g)  Notwithstanding  anything in this Agreement to the contrary,  from and
after the first  occurrence  of an event  described  in Section  11(a)(ii),  any
Rights  beneficially  owned  by (i)  an  Acquiring  Person  or an  Associate  or
Affiliate of an Acquiring  Person,  (ii) a transferee of an Acquiring Person (or
of any such Associate or Affiliate) who becomes a transferee after the Acquiring
Person (or any such Associate or Affiliate)  becomes such, or (iii) a transferee
of an Acquiring  Person (or of any such  Associate or  Affiliate)  who becomes a
transferee prior to or concurrently  with the Acquiring Person becoming such and
receives  such  Rights  pursuant  to either (A) a transfer  (whether  or not for
consideration) from the Acquiring Person (or any such Associate or Affiliate) to
holders of equity  interests in such Acquiring  Person (or any such Associate or
Affiliate)  or to any  Person  with  whom  the  Acquiring  Person  (or any  such
Associate  or  Affiliate)   has  any   continuing   agreement,   arrangement  or
understanding  regarding  the  transferred  Rights  or (B) a  transfer  which  a
majority  of the  Board  has  determined  is  part  of a  plan,  arrangement  or
understanding  which has as a primary  purpose or effect the  avoidance  of this
Section  7(g),  shall  become null and void  without  any further  action and no
holder of such  Rights  shall have any rights  whatsoever  with  respect to such
Rights, whether under any provision of this Agreement or otherwise.  The Company
shall use all  reasonable  efforts to insure that the provisions of this Section
7(g) are  complied  with,  but shall  have no  liability  to any holder of Right
Certificates   or  other  Person  as  a  result  of  its  failure  to  make  any
determinations with respect to an Acquiring Person or its Affiliates, Associates
or  transferees  hereunder.  No Right  Certificate  shall be issued  pursuant to
Section 3 that represents Rights beneficially owned by an Acquiring Person whose
Rights  would be void  pursuant to the  preceding  sentence or any  Associate or
Affiliate  thereof;  no Right  Certificate  shall be issued at any time upon the
transfer  of any  Rights  to an  Acquiring  Person  whose  Rights  would be void
pursuant to the preceding  sentence or any Associate or Affiliate  thereof or to
any nominee of such  Acquiring  Person,  Associate or  Affiliate;  and any Right
Certificate  delivered to the Rights  Agent for transfer to an Acquiring  Person
(or any  Associate,  Affiliate  or nominee  thereof)  whose Rights would be void
pursuant to the preceding sentence shall be canceled.

     Section 8.  Cancellation and Destruction of Right  Certificates.  All Right
Certificates  surrendered  for the  purpose  of  exercise,  transfer,  split up,
combination  or exchange  shall,  if surrendered to the Company or to any of its
agents,  be delivered to the Rights Agent for  cancellation or in canceled form,
or, if  surrendered  to the Rights Agent,  shall be canceled by it, and no Right
Certificates  shall be issued in lieu thereof  except as expressly  permitted by
any of the provisions of this Rights Agreement. The Company shall deliver to the
Rights  Agent for  cancellation  and  retirement,  and the Rights Agent shall so
cancel and retire,  any other  Right  Certificate  purchased  or acquired by the

                                      -9-

<PAGE>

Company otherwise than upon the exercise thereof. The Rights Agent shall deliver
all canceled Right Certificates to the Company, or shall, at the written request
of the Company, destroy such canceled Right Certificates, and in such case shall
deliver  a  certificate  of  destruction  thereof  to the  Company.

     Section  9.  Reservation  and  Availability  of  Shares.  (a)  The  Company
covenants and agrees that it will cause to be reserved and kept available out of
its  authorized  and  unissued  Preferred  Shares or any  authorized  and issued
Preferred Shares held in its treasury,  the number of Preferred Shares that will
be sufficient to permit the exercise in full of all outstanding Rights.

     (b) So long as the Common or Preferred Shares and,  following the time that
a Person  becomes an Acquiring  Person,  other  securities,  as the case may be,
issuable  upon the exercise of Rights may be listed on any  national  securities
exchange or automated  quotation system,  the Company shall use its best efforts
to cause, from and after such time as the Rights become exercisable,  all shares
reserved for such issuance to be listed on such exchange or automated  quotation
system upon official notice of issuance upon such exercise.

     (c) If  necessary  to permit the  issuance  of Common or  Preferred  Shares
pursuant to the Rights,  the Company  shall use its best  efforts from and after
such time as the Rights become  exercisable to register such Common or Preferred
Shares and, following the time that a Person becomes an Acquiring Person,  other
securities,  as the case may be, under the  Securities  Act, and any  applicable
state securities laws, cause such registration  statement to become effective as
soon as possible after such filing and keep such  registration  effective  until
the  earlier  of the  expiration  date of the Rights or the date as of which the
Rights are no longer  exercisable.  The Company may temporarily  suspend,  for a
period of time not to exceed 90 days, the  exercisability of the Rights in order
to prepare and file a registration statement under the Securities Act and permit
it to become  effective.  Upon any such  suspension,  the Company  shall issue a
public  announcement  stating  that the  exercisability  of the  Rights has been
temporarily  suspended,  as well as a public  announcement  at such  time as the
suspension  is no  longer  in  effect.  Notwithstanding  any  provision  of this
Agreement  to  the  contrary,  the  Rights  shall  not  be  exercisable  in  any
jurisdiction unless the requisite  qualification in such jurisdiction shall have
been obtained and until a  registration  statement  under the Securities Act (if
required) shall have been declared effective.

     (d) The Company  covenants  and agrees that it will take all such action as
may be necessary to ensure that all Preferred  Shares or Common Shares delivered
upon exercise of Rights shall, at the time of delivery of the  certificates  for
such  Preferred  Shares or Common  Shares  (subject  to payment of the  Purchase
Price),  be  duly  and  validly   authorized  and  issued  and  fully  paid  and
nonassessable shares.

     (e) The Company further  covenants and agrees that it will pay when due and
payable  any and all federal and state  transfer  taxes and charges  that may be
payable in respect of the issuance or delivery of the Right  Certificates  or of

                                      -10-

<PAGE>

any Preferred  Shares or Common Shares upon the exercise of Rights.  The Company
shall not,  however,  be required to pay any transfer tax that may be payable in
respect of any  transfer  or delivery of Right  Certificates  to a person  other
than, or the issuance or delivery of certificates or depositary receipts for the
Preferred  Shares or Common Shares in a name other than that of, the  registered
holder of the Right Certificate evidencing Rights surrendered for exercise or to
issue or deliver any certificates or depositary receipts for Preferred Shares or
Common Shares upon the exercise of any Rights until any such tax shall have been
paid (any such tax being payable by the holder of such Right  Certificate at the
time  of  surrender)  or  until  it  has  been   established  to  the  Company's
satisfaction that no such tax is due.

     Section 10.  Record  Date.  Each person in whose name any  certificate  for
Preferred  Shares or Common  Shares is issued upon the  exercise of Rights shall
for all purposes be deemed to have become the holder of record of the  Preferred
Shares or Common Shares  represented  thereby on, and such certificate  shall be
dated, the date upon which the Right Certificate evidencing such Rights was duly
surrendered  and  payment of the  Purchase  Price (and any  applicable  transfer
taxes)  was made;  provided,  however,  that if the date of such  surrender  and
payment  is a date upon which the  Preferred  Shares or Common  Shares  transfer
books of the Company are closed,  such person shall be deemed to have become the
record holder of such shares on, and the  certificate  shall be dated,  the next
succeeding  Business Day on which the Preferred Shares or Common Shares transfer
books of the Company  are open.  Prior to the  exercise of the Rights  evidenced
thereby,  the holder of a Right  Certificate shall not be entitled to any rights
of a holder of Preferred  Shares or Common  Shares for which the Rights shall be
exercisable,  including,  without  limitation,  the  right to vote,  to  receive
dividends or other distributions or to exercise any preemptive rights, and shall
not be entitled to receive any notice of any proceedings of the Company,  except
as provided herein.

     Section 11.  Adjustment  of Purchase  Price,  Number of Shares or Number of
Rights. The Purchase Price, the number of Preferred Shares covered by each Right
and the number of Rights outstanding are subject to adjustment from time to time
as  provided in this  Section 11. (a) (i) In the event the Company  shall at any
time after the date of this  Agreement  (A) declare a dividend on the  Preferred
Shares  payable in Preferred  Shares,  (B)  subdivide  or split the  outstanding
Preferred  Shares into a greater  number of  Preferred  Shares,  (C) combine the
outstanding  Preferred  Shares into a smaller number of Preferred  Shares or (D)
issue any shares of its capital  stock in a  reclassification  of the  Preferred

                                      -11-
<PAGE>

Shares  (including  any  reclassification  in connection  with a  consolidation,
merger or statutory  share  exchange in which the Company is the  continuing  or
surviving corporation),  except as otherwise provided in this Section 11(a), the
Purchase  Price in effect at the time of the record date for such dividend or of
the effective date of such subdivision,  split, combination or reclassification,
and the number and kind of Preferred Shares (or other capital stock) issuable on
such date,  shall be  proportionately  adjusted  so that the holder of any Right
exercised after such time shall be entitled to receive the aggregate  number and
kind of Preferred  Shares which,  if such Right had been  exercised  immediately
prior to such date and at a time when the Preferred Shares transfer books of the
Company  were open,  the holder  would  have owned upon such  exercise  and been
entitled to receive by virtue of such dividend,  subdivision, split, combination
or reclassification; provided, however, that in no event shall the consideration
to be paid upon the exercise of one Right be less than the  aggregate  par value
of the shares of capital  stock of the  Company  issuable  upon  exercise of one
Right.  If an event occurs  which would  require an  adjustment  under both this
Section 11(a)(i) and Section  11(a)(ii) hereof,  the adjustment  provided for in
this Section  11(a)(i)  shall be in addition to, and shall be made prior to, any
adjustment required pursuant to Section 11(a)(ii) hereof.

          (ii) In the event that any Person  becomes an Acquiring  Person,  then
     proper  provision  shall be made so that each holder of a Right,  except as
     provided below,  shall  thereafter  have a right to receive,  upon exercise
     thereof at the then current  Purchase Price in accordance with the terms of
     this Agreement and in lieu of such number of Preferred Shares for which the
     Right is then  exercisable,  such number of Common Shares of the Company as
     shall  equal  the  result  obtained  by (x)  multiplying  the then  current
     Purchase Price by the number of one  one-thousandths  of a Preferred  Share
     for which a Right is then  exercisable and dividing that product by (y) 50%
     of the then  current  per share  market  price of the Common  Shares of the
     Company (determined  pursuant to Section 11(d)) on the date of an Acquiring
     Person having become such; provided,  however, that if the transaction that
     would  otherwise  give rise to the foregoing  adjustment is also subject to
     the provisions of Section 13 hereof, then only the provisions of Section 13
     hereof shall apply and no adjustment shall be made pursuant to this Section
     11(a)(ii).  At its  discretion,  the Board of  Directors of the Company may
     provide that holders of Rights,  upon exercise thereof,  shall receive,  in
     lieu of  Common  Shares,  such  number  of one  thousandths  of a share  of
     Preferred  Shares as shall equal the result obtained by (X) multiplying the
     then current Purchase Price by the number of one one-thousandths of a share
     of Preferred  Shares for which a Right is then exercisable and dividing the
     product  by (Y) 50% of the  then  current  per  share  market  price of the
     Company's  Common Shares  (determined  pursuant to Section 11(d) hereof) on
     the date an Acquiring Person becomes such.  Notwithstanding  the foregoing,
     upon the occurrence of any of the events listed above in this  subparagraph
     (ii),  any  Rights  that are or were  beneficially  owned  on or after  the

                                      -12-
<PAGE>

     earlier  of the  Distribution  Date  or the  Share  Acquisition  Date by an
     Acquiring  Person (or any Associate or Affiliate of such Acquiring  Person)
     shall become null and void in  accordance  with the  provisions  of Section
     7(g) of this Agreement and any holder of such Rights shall  thereafter have
     no right to exercise such Rights under any provision of this Agreement.

          (iii) Any Right Certificate issued pursuant to Section 3 or Section 22
     hereof that represents Rights  beneficially owned by an Acquiring Person or
     any Associate or Affiliate thereof and any Right Certificate  issued at any
     time  upon  the  transfer  of any  Rights  to an  Acquiring  Person  or any
     Associate or Affiliate  thereof or to any nominee of such Acquiring Person,
     Associate  or  Affiliate,  and any Right  Certificate  issued  pursuant  to
     Section 6 hereof or this Section 11 upon transfer, exchange, replacement or
     adjustment  of any other Right  Certificate  referred to in this  sentence,
     shall contain the following legend:

      The Rights  represented  by this Right  Certificate  are or were
      beneficially  owned by a Person  who was or became an  Acquiring
      Person or an Affiliate  or an  Associate of an Acquiring  Person
      (as such  terms  are  defined  in the  Rights  Agreement).  This
      Right Certificate and the Rights  represented  hereby may become
      null  and  void  in  the  circumstances   specified  in  Section
      11(a)(ii) of the Rights Agreement.

          (iv) In the event that an event specified in Section  11(a)(ii) occurs
     and there  shall  not be  sufficient  treasury  shares  or  authorized  but
     unissued  Common  Shares to permit  the  exercise  in full of the Rights in
     accordance  with  Section  11(a)(ii)  and the  Board of  Directors  has not
     exercised its discretion  pursuant to Section  11(a)(ii) to provide for the
     issuance of  Preferred  Shares in lieu of Common  Shares,  then the Company
     shall use its best efforts to carry out all such action as may be necessary
     to authorize  additional  Common  Shares for issuance  upon exercise of the
     Rights;  provided,   however,  if  the  Company  is  unable  to  cause  the
     authorization  of  additional  Common Shares  sufficient  for issuance upon
     exercise  of the  Rights  within  forty-five  (45)  days  from the date the
     adjustment was required, the Company shall: (A) determine the excess of (1)
     the value of the Common Shares (the  "Exercise  Shares")  issuable upon the
     exercise  of a Right  (the  "Current  Value")  over  (2) the  then  current
     Purchase Price (such excess,  the  "Spread"),  and (B) with respect to each
     Right, make adequate provision to substitute for the Exercise Shares,  upon
     payment of the applicable  Purchase Price, (1) cash, (2) a reduction in the
     Purchase Price, (3) Common Shares or other equity securities of the Company

                                      -13-
<PAGE>

     (including,  without  limitation,  shares, or units of shares, of preferred
     stock  which the Board of  Directors  of the Company has deemed to have the
     same value as Common Shares of the Company (such shares of preferred  stock
     being "common share equivalents")), (4) debt securities of the Company, (5)
     other assets, or (6) any combination of the foregoing,  having an aggregate
     value  equal to the  Current  Value,  where such  aggregate  value has been
     determined  by the Board of Directors of the Company  based upon the advice
     of a nationally recognized investment banking firm selected by the Board of
     Directors of the Company; provided,  however, if the Company shall not have
     made  adequate  provision  to deliver  value  pursuant  to clause (B) above
     within  thirty (30) days (which  30-day period may be extended by the Board
     of Directors for up to two additional  30-day periods)  following the first
     occurrence  of a  Section  11(a)(ii)  event,  then  the  Company  shall  be
     obligated  to  deliver,  upon the  surrender  for  exercise  of a Right and
     without  requiring  payment of the Purchase  Price,  Common  Shares (to the
     extent  available) and then, if necessary,  cash,  securities and/or assets
     which in the  aggregate  are equal to the  Spread.  To the extent  that the
     Company  determines  that  some  action  need  be  taken  pursuant  to this
     subparagraph  (iv),  the  Company  (x) shall  provide,  subject to the last
     sentence of subparagraph (ii) of this Section 11(a), that such action shall
     apply  uniformly  to all  outstanding  Rights,  and  (y)  may  suspend  the
     exercisability  of the Rights for such time as may be reasonably  necessary
     in order to seek any  authorization  of additional  shares and/or to decide
     the  appropriate  form of  distribution  to be made pursuant  hereto and to
     determine the value thereof.

     (b) In case the Company shall fix a record date for the issuance of rights,
options or warrants to all holders of  Preferred  Shares  entitling  them (for a
period expiring within 45 calendar days after such record date) to subscribe for
or purchase  Preferred Shares (or shares having the same rights,  privileges and
preferences  as  the  Preferred  Shares  ("equivalent   preferred  shares"),  or
securities convertible into Preferred Shares or equivalent preferred shares at a
price per Preferred Share or equivalent  preferred share (or having a conversion
price per Preferred  Share, if a security  convertible  into Preferred Shares or
equivalent preferred shares) less than the current per share market price of the
Preferred Shares (as defined in Section 11(d)) on such record date, the Purchase
Price to be in effect after such record date shall be determined by  multiplying
the  Purchase  Price  in  effect  immediately  prior  to such  record  date by a
fraction,  the  numerator  of which  shall be the  number  of  Preferred  Shares
outstanding  on such record date plus the number of  Preferred  Shares which the
aggregate  offering  price  of the  total  number  of  Preferred  Shares  and/or
equivalent  preferred  shares so to be offered  (and/or  the  aggregate  initial
conversion price of the convertible  securities so to be offered) would purchase
at such current market price and the denominator of which shall be the number of
Preferred  Shares  outstanding on such record date plus the number of additional
Preferred  Shares  and/or   equivalent   preferred  shares  to  be  offered  for

                                      -14-
<PAGE>

subscription  or purchase  (or into which the  convertible  securities  so to be
offered are initially  convertible);  provided,  however, that in no event shall
the  consideration  to be paid upon the  exercise  of one Right be less than the
aggregate par value of the shares of capital stock issuable upon exercise of the
Right. In case such  subscription  price may be paid in a consideration  part or
all of which may be in a form other than cash,  the value of such  consideration
shall be as  determined  in good faith by the Board of Directors of the Company,
whose  determination  shall be  described  in a statement  filed with the Rights
Agent and shall be binding on the Rights  Agent and the  holders of the  Rights.
Preferred  Shares  owned by or held for the account of the Company  shall not be
deemed  outstanding  for the purpose of any such  computation.  Such  adjustment
shall be made  successively  whenever  such a record  date is fixed;  and in the
event that such rights or warrants are not so issued,  the Purchase  Price shall
be  adjusted  to be the  Purchase  Price  which  would then be in effect if such
record date had not been fixed.

     (c) In case the  Company  shall  fix a  record  date  for the  making  of a
distribution  to all  holders  of  the  Preferred  Shares  (including  any  such
distribution  made in  connection  with a  consolidation  or merger in which the
Company is the continuing or surviving corporation) of evidences of indebtedness
or assets (other than a regular quarterly cash dividend or a dividend payable in
Preferred Shares) or subscription  rights or warrants  (excluding those referred
to in Section 11(b)),  the Purchase Price to be in effect after such record date
shall be  determined by  multiplying  the Purchase  Price in effect  immediately
prior to such  record date by a fraction,  the  numerator  of which shall be the
current per share  market price of the  Preferred  Shares (as defined in Section
11(d)) on such record date,  less the fair market value (as  determined  in good
faith by the Board of  Directors of the Company,  whose  determination  shall be
described  in a  statement  filed with the Rights  Agent) of the  portion of the
assets or evidences of  indebtedness  to be distributed  or of the  subscription
rights or warrants  applicable to one  Preferred  Share and the  denominator  of
which shall be the  current  per share  market  price of the  Preferred  Shares;
provided,  however, that in no event shall the consideration to be paid upon the
exercise  of one Right be less  than the  aggregate  par value of the  shares of
capital  stock of the  Company to be issued  upon  exercise  of one Right.  Such
adjustments shall be made successively whenever such a record date is fixed; and
in the event that such  distribution is not made, the Purchase Price shall again
be adjusted to be the Purchase Price that would be in effect if such record date
had not been  fixed.

     (d) For the purpose of any  computation  hereunder,  the "current per share
market  price" of any  security (a  "Security"  for the purposes of this Section
11(d)(i))  on any date shall be deemed to be the  average  of the daily  closing
prices per share of such Security for the 30  consecutive  Trading Days (as such
term is hereinafter defined) immediately prior to such date; provided,  however,
that in the event that the current per share  market  price of such  Security is
determined  during a period  following  the  announcement  by the  issuer of the
Security of (1) a dividend or distribution on such Security payable in shares of
such  Security  or  securities   convertible  into  such  shares,   or  (2)  any

                                      -15-

<PAGE>

subdivision,  combination or reclassification of such Security, and prior to the
expiration of 30 consecutive  Trading Days after the  ex-dividend  date for such
dividend or distribution,  or the record date for such subdivision,  combination
or reclassification,  then, and in each such case, the "current per share market
price" shall be  appropriately  adjusted to reflect the current market price per
share  equivalent of such Security.  The closing price for each day shall be the
last sale price,  regular way, or, in case no such sale takes place on such day,
the average of the closing bid and asked prices,  regular way, in either case as
reported in the principal consolidated transaction reporting system with respect
to securities  listed or admitted to trading on the New York Stock  Exchange or,
if the  Security  is not  listed or  admitted  to  trading on the New York Stock
Exchange, as reported in the principal consolidated transaction reporting system
with respect to securities listed on the principal national  securities exchange
on which the  Security is listed or  admitted to trading or, if the  Security is
not listed or admitted to trading on any national securities exchange,  the last
quoted sale price or, if not so quoted, the average of the closing bid and asked
prices in the  over-the-counter  market, as reported by the National Association
of Securities Dealers,  Inc. Automated Quotations System ("NASDAQ") or any other
system  then in use,  or, if on any such date the  Security is not quoted by any
such organization,  the average of the closing bid and asked prices as furnished
by a professional  market maker making a market in the Security  selected by the
Board of Directors of the Company. If on any such date no market maker is making
a market in a Security, the closing price of such Security shall be deemed to be
the fair  value of such  Security  as  determined  in good faith by the Board of
Directors of the Company.  The term  "Trading Day" shall mean a day on which the
principal  national  securities  exchange  on which  the  Security  is listed or
admitted to trading is open for the  transaction of business or, if the Security
is not listed or  admitted to trading on any  national  securities  exchange,  a
Business Day.

     (e) No  adjustment  in the  Purchase  Price shall be  required  unless such
adjustment  would require an increase or decrease of at least l% in the Purchase
Price;  provided,  however, that any adjustments which by reason of this Section
11(e) are not  required  to be made  shall be  carried  forward  and taken  into
account in any subsequent  adjustment.  All  calculations  under this Section 11
shall be made to the nearest cent or to the nearest  ten-thousandth  of a Common
Share or other share or  one-millionth of a Preferred Share, as the case may be.
Notwithstanding  the  first  sentence  of this  Section  11(e),  any  adjustment
required by this Section 11 shall be made no later than the earlier of (i) three
years from the date of the transaction that requires such adjustment or (ii) the
date of the expiration of the right to exercise any Rights

     (f) If as a result of an  adjustment  made pursuant to Section  11(a),  the
holder of any Right  thereafter  exercised  shall become entitled to receive any
shares of capital stock of the Company other than Preferred  Shares,  thereafter
the number of such other shares so  receivable  upon exercise of any Right shall
be  subject to  adjustment  from time to time in a manner and on terms as nearly
equivalent as practicable to the provisions with respect to the shares contained
in Section 11(a),  11(b),  11(c) and 11(i), and the provisions of Sections 7, 9,
10 and 13 with respect to the Preferred  Shares shall apply on like terms to any
such other shares.
                
                                      -16-
<PAGE>

     (g)  All  Rights  originally  issued  by  the  Company  subsequent  to  any
adjustment  made to the Purchase  Price  hereunder  shall  evidence the right to
purchase,  at the  adjusted  Purchase  Price,  the  number of  Preferred  Shares
purchasable from time to time hereunder upon exercise of the Rights, all subject
to further adjustment as provided herein.

     (h) Unless the Company  shall have  exercised  its  election as provided in
Section  11(i),  upon each  adjustment of the Purchase  Price as a result of the
calculations made in Section 11(b) and (c), each Right  outstanding  immediately
prior to the making of such adjustment  shall  thereafter  evidence the right to
purchase,  at the adjusted Purchase Price, that number of one one-thousandths of
a Preferred Share (calculated to the nearest one-millionth of a Preferred Share)
obtained by (i) multiplying (x) the number of one one-thousandths of a Preferred
Share  covered  by a  Right  immediately  prior  to this  adjustment  by (y) the
Purchase Price in effect  immediately  prior to such  adjustment of the Purchase
Price, and (ii) dividing the product so obtained by the Purchase Price in effect
immediately after such adjustment of the Purchase Price.

     (i) The  Company  may elect on or after the date of any  adjustment  of the
Purchase  Price  to  adjust  the  number  of  Rights,  in  substitution  for any
adjustment in the number of Preferred Shares  purchasable upon the exercise of a
Right.  Each of the Rights  outstanding  after such  adjustment of the number of
Rights shall be exercisable for the number of one one-thousandths of a Preferred
Share for which a Right was exercisable  immediately  prior to such  adjustment.
Each Right held of record prior to such adjustment of the number of Rights shall
become that number of Rights (calculated to the nearest ten-thousandth) obtained
by dividing the Purchase Price in effect  immediately prior to adjustment of the
Purchase Price by the Purchase Price in effect  immediately  after adjustment of
the Purchase Price.  The Company shall make a public  announcement of, and shall
notify  the  Rights  Agent of,  its  election  to adjust  the  number of Rights,
indicating  the record date for the  adjustment,  and, if known at the time, the
amount of the  adjustment to be made.  This record date may be the date on which
the  Purchase  Price  is  adjusted  or any day  thereafter,  but,  if the  Right
Certificates have been issued,  shall be at least 10 days later than the date of
the public  announcement.  If Right  Certificates  have been  issued,  upon each
adjustment of the number of Rights  pursuant to this Section 11(i),  the Company
shall, as promptly as practicable,  cause to be distributed to holders of record
of Right Certificates on such record date Right Certificates evidencing, subject
to  Section 14  hereof,  the  additional  Rights to which the  holders  shall be
entitled as a result of the adjustment,  or, at the option of the Company, shall
cause to be distributed to the holders of record in substitution and replacement
for the Right  Certificates held by the holders prior to the date of adjustment,
and upon surrender thereof,  if required by the Company,  new Right Certificates
evidencing  all the Rights to which the  holders  shall be  entitled  after such

                                      -17-

<PAGE>

adjustment.  Right Certificates to be distributed shall be issued,  executed and
countersigned  in the manner provided for herein (and may bear, at the option of
the Company,  the adjusted  Purchase Price) and shall be registered in the names
of the holders of record of Right  Certificates  on the record date specified in
the public announcement.

     (j)  Irrespective  of any adjustment or change in the Purchase Price or the
number of Preferred  Shares issuable upon the exercise of the Rights,  the Right
Certificates  theretofore  and  thereafter  issued may  continue  to express the
Purchase  Price per one  one-thousandth  of a Preferred  Share and the number of
shares which were expressed in the initial Right  Certificates  issued hereunder
but they shall be deemed to represent the Purchase Price and number of Preferred
Shares as adjusted from time to time hereunder.
                
     (k) Before  taking any action that would cause an  adjustment  reducing the
Purchase Price below one  one-thousandth  of the then par value,  if any, of the
Preferred  Shares  issuable upon exercise of the Rights,  the Company shall take
any corporate  action which may, in the opinion of its counsel,  be necessary in
order  that  the  Company   may  validly  and  legally   issue  fully  paid  and
nonassessable Preferred Shares at the adjusted Purchase Price.

     (l) In any case in which this Section 11 shall  require that an  adjustment
in the  Purchase  Price be made  effective  as of a record  date for a specified
event,  the Company may elect to defer  until the  occurrence  of such event the
issuing  to the holder of any Right  exercised  after  such  record  date of the
Preferred  Shares and other capital stock or securities of the Company,  if any,
issuable  upon  such  exercise  over and above the  Preferred  Shares  and other
capital stock or securities of the Company,  if any, issuable upon such exercise
on the basis of the Purchase Price in effect prior to the adjustment;  provided,
however,  that the  Company  shall  deliver  to such  holder a due bill or other
appropriate instrument evidencing such holder's right to receive such additional
shares upon the occurrence of the event requiring the adjustment.
               
     (m)  Anything  in this  Section  11 to the  contrary  notwithstanding,  the
Company shall be entitled to make  reductions in the Purchase Price, in addition
to those adjustments expressly required by this Section 11, as and to the extent
that it in its sole discretion shall determine to be advisable in order that any
(i) consolidation or subdivision of the Preferred  Shares,  (ii) issuance wholly
for cash of any of the Preferred  Shares at less than the current  market price,
(iii) issuance wholly for cash of Preferred  Shares or securities which by their
terms are convertible  into or  exchangeable  for Preferred  Shares,  (iv) stock
dividends  or (v)  issuance of rights,  options or warrants  referred to in this
Section 11,  hereafter  made by the Company to holders of its  Preferred  Shares
shall not be taxable to such shareholders.

                                      -18-

<PAGE>

     Section 12.  Certificate  of Adjusted  Purchase  Price or Number of Shares.
Whenever an  adjustment  is made as  provided in Sections 11 and 13 hereof,  the
Company shall (a) promptly  prepare a certificate  setting forth the adjustment,
and a brief statement of the facts  accounting for the adjustment,  (b) promptly
file with the Rights Agent and with each transfer agent for the Common Shares or
the  Preferred  Shares a copy of the  certificate  and (c) mail a brief  summary
thereof to each holder of a Right  Certificate  in  accordance  with  Section 25
hereof.

     Section 13.  Consolidation  Merger or Sale or Transfer of Assets or Earning
Power.  (a) In the event that  following  the  Distribution  Date,  directly  or
indirectly,  (w) the Company shall consolidate with, or merge with and into, any
other Person,  (x) any Person shall consolidate with the Company,  or merge with
and into the  Company  and the  Company  shall be the  continuing  or  surviving
corporation of such merger and, in connection  with such merger,  all or part of
the  Common  Shares  shall  be  changed  into or  exchanged  for  stock or other
securities  of any  other  Person  (or of the  Company)  or  cash  or any  other
property,  (y) the Company shall engage in any statutory share exchange  whereby
the Company's  Common Shares are converted into stock,  securities,  cash or any
other  property of any other  Person or (z) the Company  shall sell or otherwise
transfer (or one or more of its Subsidiaries shall sell or otherwise  transfer),
in one or more transactions,  assets or earning power aggregating 50% or more of
the assets or earning  power of the  Company  and its  Subsidiaries  (taken as a
whole) to any other  Person  other than the  Company or any of its wholly  owned
Subsidiaries,  then, on the first occurrence of any such event, proper provision
shall be made so that (i) each  holder of a Right,  other than  Rights that have
become void pursuant to Section  11(a)(ii)  hereof,  shall  thereafter  have the
right to receive, upon the exercise thereof at a price equal to the then current
Purchase Price in accordance  with the terms of this  Agreement,  such number of
validly issued,  fully paid,  nonassessable and freely tradable Common Shares of
the Principal Party (as hereinafter  defined),  in lieu of Preferred  Shares for
which a Right is then  exercisable,  not  subject to any rights of call or first
refusal,  as shall be equal to the result  obtained by (1)  multiplying the then
current Purchase Price by the number of one one-thousandths of a Preferred Share
for which a Right is then  exercisable  and (2) dividing  that product by 50% of
the then current per share market  price of the Common  Shares of the  Principal
Party (determined pursuant to Section 11(d)) on the date of consummation of such
consolidation,  merger,  statutory share exchange,  sale or transfer;  provided,
however,  that the  Purchase  Price  and the  number  of  Common  Shares of such
Principal  Party issuable upon exercise of each Right shall be further  adjusted
as provided in Section 11(f) of this  Agreement to reflect any events  occurring
in respect of such Principal Party after the date of such consolidation, merger,
statutory  share  exchange,  sale or transfer;  (ii) the  Principal  Party shall
thereafter  be liable for, and shall  assume,  by virtue of such  consolidation,
merger,  statutory  share  exchange,  sale or transfer,  all the obligations and
duties of the Company pursuant to this Agreement; (iii) the term "Company" shall
thereafter  be deemed to refer to the  Principal  Party,  it being  specifically

                                      -19-
<PAGE>

intended  that the  provisions of Section 11 hereof shall apply to the Principal
Party;  and (iv) the Principal Party shall take such steps  (including,  but not
limited  to, the  reservation  of a  sufficient  number of its Common  Shares in
accordance  with Section 9 hereof) in connection  with such  consummation of any
transaction  as may be  necessary  to assure that the  provisions  hereof  shall
thereafter be  applicable,  as nearly as  reasonably  may be, in relation to the
Common Shares thereafter deliverable upon the exercise of the Rights;  provided,
however,  that,  upon the subsequent  occurrence of any  consolidation,  merger,
statutory  share  exchange,  sale or transfer  of assets or other  extraordinary
transaction  in respect of such  Principal  Party,  each holder of a Right shall
thereupon  be entitled to receive,  upon  exercise of a Right and payment of the
Purchase Price as provided in this Section 13(a), and such Principal Party shall
take such steps (including,  but not limited to, reservation of shares of stock)
as may be  necessary  to  permit  the  subsequent  exercise  of  the  Rights  in
accordance  with the terms hereof for such cash,  shares,  rights,  warrants and
other property.

          (b) "Principal Party" shall mean:

               (i) in the case of any  transaction  described in (w), (x) or (y)
          of the first sentence of Section 13(a),  the Person that is the issuer
          of  any  securities  into  which  Common  Shares  of the  Company  are
          converted in such merger,  consolidation  or statutory share exchange,
          or, if there is more  than one such  issuer,  the  issuer  the  Common
          Shares  of which has the  greatest  aggregate  market  value of shares
          outstanding, or if no securities are so issued, (A) the Person that is
          the  other  party to the  merger,  consolidation  or  statutory  share
          exchange,  if such  Person  survives  said merger or  statutory  share
          exchange,  or, if there is more than one such  Person,  the Person the
          Common  Shares of which has the  greatest  aggregate  market  value of
          shares outstanding or (B) if the Person that is the other party to the
          merger or  statutory  share  exchange  does not  survive the merger or
          statutory share  exchange,  the Person that does survive the merger or
          statutory share exchange (including the Company if it survives) or (C)
          the Person resulting from the consolidation.

               (ii) in the case of any transaction described in (z) of the first
          sentence in this  Section  13, the Person that is the party  receiving
          the  greatest  portion  of the  assets or  earning  power  transferred
          pursuant to such transaction or transactions,  or, if each Person that
          is a party  to such  transaction  or  transactions  receives  the same
          portion of the assets or earning power so transferred or if the Person
          receiving  the greatest  portion of the assets or earning power cannot
          be  determined,  whichever  of such  Persons  is the  issuer of Common
          Shares   having  the  greatest   aggregate   market  value  of  shares
          outstanding;  provided,  however,  that in any such  case,  (x) if the
          Common  Shares of such  Person  are not at such time and have not been
          continuously  during the preceding  12-month period  registered  under
          Section 12 of the Exchange Act and such Person is a direct or indirect
          subsidiary  of another  Person the Common Shares of which are and have

                                      -20-

<PAGE>

          been so  registered,  "Principal  Party"  shall  refer  to such  other
          Person;  (y)  in  case  such  Person  is  a  subsidiary,  directly  or
          indirectly, of more than one Person, the Common Shares of all of which
          are and have been so  registered,  "Principal  Party"  shall  refer to
          whichever  of such Persons is the issuer of the Common  Shares  having
          the greatest aggregate market value of shares outstanding,  and (z) in
          case such Person is owned, directly or indirectly,  by a joint venture
          formed  by two or  more  Persons  that  are  not  owned,  directly  or
          indirectly,  by the same  Person,  the  rules set forth in (x) and (y)
          above  shall  apply to each of the owners  having an  interest in such
          joint  venture  as if the  Person  owned by the joint  venture  were a
          "subsidiary"  of both or all of such joint venturers and the Principal
          Parties in each such case shall bear the obligations set forth in this
          Section 13 in the same ratio as their direct or indirect  interests in
          such Person bear to the total of such interests.

     (c) The  Company  shall  not  consummate  any such  consolidation,  merger,
statutory share exchange,  sale or transfer unless prior thereto the Company and
the  Principal  Party shall have  executed  and  delivered to the Rights Agent a
supplemental  agreement  providing for the terms set forth in paragraphs (a) and
(b) of this Section 13 and further  providing that, as soon as practicable after
the  date  of any  consolidation,  merger,  statutory  share  exchange,  sale or
transfer  mentioned in paragraph  (a) of this  Section 13, the  Principal  Party
will:

               (i) prepare and file a registration statement under the Act, with
          respect to the Rights and the securities  purchasable upon exercise of
          the Rights on an appropriate  form, use its best efforts to cause such
          registration  statement  to become  effective  as soon as  practicable
          after such filing and use its best efforts to cause such  registration
          statement to remain  effective (with a prospectus at all times meeting
          the  requirements  of the Act)  until  the date of  expiration  of the
          Rights and similarly comply with applicable state securities laws;

               (ii) deliver to holders of the Rights  financial  statements  for
          the  Principal  Party and each of its  Affiliates  which comply in all
          respects with the  requirements  for registration on Form 10 under the
          Exchange Act;

               (iii) use its best efforts, if the Common Shares of the Principal
          Party  shall  be  listed  or  admitted  to  trading  on  any  national
          securities  exchange or quoted on any automated  quotation  system, to
          list or admit to trading (or  continue  the listing or trading of) the
          Rights and the securities  purchasable  upon exercise of the Rights on
          such  national   securities  exchange  or  have  the  Rights  or  such
          securities  quoted on such  automated  quotation  system  and,  if the
          Common Shares of the  Principal  Party shall not be listed or admitted
          to  trading  on any  national  securities  exchange  or  quoted on any
          automated  quotation  system,  to cause the Rights and the  securities
          purchasable  upon  exercise  of the Rights to be listed or admitted to
          trading on a national  securities  exchange or quoted in an  automated
          quotation system then in use; and

               (iv) obtain  waivers of any rights of first refusal or preemptive
          rights in respect of the Common Shares of the Principal  Party subject
          to purchase upon exercise of  outstanding  Rights.

                                      -21-

<PAGE>

The provisions of this Section 13 shall similarly apply to successive mergers or
consolidations or statutory share exchanges or sales or other transfers.  In the
event that one of the transactions described in Section 13(a) hereof shall occur
at any time after the occurrence of a transaction described in Section 11(a)(ii)
hereof,  the Rights which have not theretofore  been exercised shall  thereafter
become exercisable in the manner described in Section 13(a).

     (d)  Furthermore,  in case the Principal  Party which is to be a party to a
transaction  referred  to in  this  Section  13  has  provision  in  any  of its
authorized securities or in its certificate of incorporation or by-laws or other
instrument  governing  its corporate  affairs,  which  provision  would have the
effect of (i) causing  such  Principal  Party to issue (other than to holders of
Rights pursuant to this Section 13), in connection with, or as a consequence of,
the consummation of a transaction  referred to in this Section 13, Common Shares
of such  Principal  Party at less than the then  current  market price per share
(determined pursuant to Section 11(d) hereof) or securities  exercisable for, or
convertible  into,  Common Shares of such Principal Party at less than such then
current market price, or (ii) providing for any special payment,  tax or similar
provisions  in  connection  with  the  issuance  of the  Common  Shares  of such
Principal  Party  pursuant to the provisions of Section 13, then, in such event,
the  Company  hereby  agrees  with  each  holder  of  Rights  that it shall  not
consummate  any such  transaction  unless  prior  thereto  the  Company and such
Principal  Party  shall  have  executed  and  delivered  to the  Rights  Agent a
supplemental  agreement  providing  that  the  provision  in  question  of  such
Principal  Party  shall  have  been  canceled,  waived or  amended,  or that the
authorized  securities shall be redeemed,  so that the applicable provision will
have no effect in connection  with, or as a consequence of, the  consummation of
the proposed transaction.

     (e) The Company  covenants and agrees not to enter into any  transaction of
the kind listed in this Section 13 if (x) at the time of such transaction  there
are  any  rights,  warrants,   instruments  or  securities  outstanding  or  any
agreements  or  arrangements  which,  as a result  of the  consummation  of such
transaction,  would  substantially  diminish or otherwise eliminate the benefits
intended to be afforded  by the Rights or (y) prior to,  simultaneously  with or
immediately  after  such  transaction,   the  stockholders  of  the  Person  who
constitute or would  constitute  the  "Principal  Party" for purposes of Section
13(a) hereof shall have received a distribution  of Rights  previously  owned by
such Person or any of its Affiliates or Associates.

     (f) If, for any reason, the Rights cannot be exercised for Common Shares of
the Company or such Principal Party, then a holder of Rights will have the right
to exchange such Rights,  without payment of the applicable  exercise price, for
cash from the Company or such  Principal  Party in an amount equal to the number
of Common  Shares he would  otherwise  be entitled to purchase  times 50% of the

                                      -22-

<PAGE>

then current market price,  as determined  pursuant to Section 11(d) hereof,  of
such Common Shares of the Company or such Principal  Party.  If, for any reason,
including, without limitation, if such Principal Party is an individual, private
partnership or private company, the foregoing cannot be applied to determine the
cash amount into which the Rights are exchangeable,  then the Board of Directors
of the Company, based upon the advice from one or more investment banking firms,
shall determine such amount reasonably and with utmost good faith to the holders
of the Rights. Any such determination shall be binding and final.

     Section 14. Fractional Rights and Fractional  Shares. (a) The Company shall
not be required to issue fractions of Rights or to distribute Right Certificates
which evidence fractional Rights. In lieu of such fractional Rights, there shall
be paid to the registered holders of the Right Certificates with regard to which
such fractional  Rights would otherwise be issuable,  an amount in cash equal to
the same fraction of the current market value of a whole Right. For the purposes
of this Section  14(a),  the current  market value of a whole Right shall be the
closing price of the Rights for the Trading Day immediately prior to the date on
which such  fractional  Rights would have been otherwise  issuable.  The closing
price for any day shall be the last sale price, regular way, or, in case no such
sale takes place on such day,  the average of the closing bid and asked  prices,
regular  way,  in  either  case  as  reported  in  the  principal   consolidated
transaction  reporting  system with respect to securities  listed or admitted to
trading  on the New York  Stock  Exchange  or, if the  Rights  are not listed or
admitted to trading on the New York Stock Exchange, as reported in the principal
consolidated  transaction  reporting system with respect to securities listed on
the  principal  national  securities  exchange on which the Rights are listed or
admitted  to trading  or, if the Rights are not listed or admitted to trading on
any  national  securities  exchange,  the last  quoted  sale price or, if not so
quoted, the average of the closing bid and asked prices in the  over-the-counter
market,  as  reported  by NASDAQ or such other  system then in use or, if on any
such date the Rights are not quoted by any such organization, the average of the
closing bid and asked prices as furnished by a professional  market maker making
a market in the Rights selected by the Board of Directors of the Company.  If on
any such date no such  market  maker is making a market in the  Rights  the fair
value of the  Rights on such date as  determined  in good  faith by the Board of
Directors of the Company shall be used.

     (b) The  Company  shall not be  required to issue  fractions  of  Preferred
Shares (other than fractions that are integral  multiples of one  one-thousandth
of a Preferred  Share) or Common  Shares upon exercise of the Rights or to issue
certificates  which evidence fractions of Preferred Shares (other than fractions
that are  integral  multiples  of one  one-thousandth  of a Preferred  Share) or
Common Shares. In lieu of fractional Common Shares, the Company shall pay to the
registered holders of Right Certificates at the time the Rights are exercised as

                                      -23-

<PAGE>

herein  provided  an amount in cash equal to the same  fraction  of the  current
market value of one Common  Share.  Fractions  of  Preferred  Shares in integral
multiples of one one-thousandth of a Preferred Share may, at the election of the
Company, be evidenced by depositary receipt pursuant to an appropriate agreement
between  the  Company  and a  depositary  selected  by it,  provided  that  such
agreement shall provide that the holders of such depositary  receipts shall have
all the  rights,  privileges  and  preferences  to which  they are  entitled  as
beneficial  owners  of the  Preferred  Shares  represented  by  such  depositary
receipts. In lieu of fractional Preferred Shares that are not integral multiples
of one  one-thousandth  of a  Preferred  Share,  the  Company  shall  pay to the
registered holders of Right Certificates at the time the Rights are exercised as
herein  provided  an amount in cash equal to the same  fraction  of the  current
market value of one Preferred  Share. For purposes of this Section 14(b) hereof,
the  current  market  value of a  Preferred  Share or Common  Share shall be the
closing  price of a  Preferred  Share  (as  determined  pursuant  to the  second
sentence of Section 11(d) hereof) for the Trading Day  immediately  prior to the
date of such exercise.

     (c) The holder of a Right by the acceptance of the Rights  expressly waives
his right to receive any fractional  Rights or any fractional  shares (except as
provided above) upon exercise of a Right.

     Section  15.  Rights of  Action.  All  rights of action in  respect of this
Agreement,  excepting  the  rights of action  given to the  Rights  Agent  under
Section 18 hereof, are vested in the respective  registered holders of the Right
Certificates (and, prior to the Distribution Date, the registered holders of the
Common Shares); and any registered holder of any Right Certificate (or, prior to
the Distribution Date, of the Common Shares),  without the consent of the Rights
Agent  or of the  holder  of any  other  Right  Certificate  (or,  prior  to the
Distribution Date, of the Common Shares), may, in his own behalf and for his own
benefit,  enforce, and may institute and maintain any suit, action or proceeding
against  the Company to enforce,  or  otherwise  act in respect of, his right to
exercise the Rights evidenced by the Right Certificate in the manner provided in
the Right  Certificate  and in this Agreement and subject to the limitations set
forth in the Right  Certificates  and in this  Agreement.  Without  limiting the
foregoing or any remedies available to the holders of Rights, it is specifically
acknowledged that the holders of Rights would not have an adequate remedy at law
for any breach of this Agreement and will be entitled to specific performance of
the  obligations  under,  and  injunctive  relief  against  actual or threatened
violations of, the obligations of any Person subject to this Agreement.

     Section  16.  Agreement  of Right  Holders.  Every  holder  of a Right,  by
accepting  the same,  consents  and agrees with the Company and the Rights Agent
and with every other holder of a Right that:

     (a) prior to the Distribution Date, the Rights will be transferable only in
connection with the transfer of the Common Shares;

                                      -24-
<PAGE>

     (b) after the  Distribution  Date, the Right  Certificates are transferable
only on the registry  books of the Rights Agent if  surrendered at the principal
office of the Rights Agent,  duly endorsed or accompanied by a proper instrument
of transfer; and 

     (c) the Company and the Rights Agent may deem and treat the person in whose
name the Right  Certificate (or, prior to the Distribution  Date, the associated
Common Shares  certificate)  is registered as the absolute  owner thereof and of
the Rights  evidenced  thereby  (notwithstanding  any  notations of ownership or
writing on the Right  Certificates or the associated  Common Shares  certificate
made by anyone  other than the  Company or the  Rights  Agent) for all  purposes
whatsoever,  and neither  the Company nor the Rights  Agent shall be affected by
any notice to the contrary.

     Section 17.  Right Certificate Holder Not Deemed a  Stockholder. No holder,
as such, of any Right Certificate  shall be entitled to vote,  receive dividends
or be  deemed  for any  purpose  the  holder of the  Common  Shares or any other
securities  of the Company  which may at any time be issuable on the exercise of
the Rights  represented  thereby,  nor shall anything contained herein or in any
Right  Certificate  be  construed  to  confer  upon  the  holder  of  any  Right
Certificate,  as such,  any of the rights of a stockholder of the Company or any
right to vote for the  election of  directors  or upon any matter  submitted  to
stockholders  at any  meeting  thereof,  or to give or  withhold  consent to any
corporate  action,  or to receive notice of meetings or other actions  affecting
stockholders (except as provided in this Agreement),  or to receive dividends or
subscription  rights, or otherwise,  until the Right or Rights evidenced by such
Right  Certificate  shall have been exercised in accordance  with the provisions
hereof.

     Section 18.  Concerning the Rights Agent.  The Company agrees to pay to the
Rights Agent reasonable  compensation for all services  rendered by it hereunder
and, from time to time, on demand of the Rights Agent,  its reasonable  expenses
and counsel  fees and other  disbursements  incurred in the  administration  and
execution  of this  Agreement  and the exercise  and  performance  of its duties
hereunder.  The Company  also agrees to  indemnify  the Rights Agent for, and to
hold it harmless  against,  any loss,  liability,  or expense,  incurred without
negligence, bad faith or willful misconduct on the part of the Rights Agent, for
anything done or omitted by the Rights Agent in connection  with the  acceptance
and  administration  of this  Agreement,  including  the costs and  expenses  of
defending  against  any  claim  of  liability  relating  to the  Rights  or this
Agreement.  In no case will the Rights  Agent be liable for  special,  indirect,
incidental or consequential  loss or damage of any kind whatsoever,  even if the
Rights Agent has been advised of the possibility of such loss or damage.

                                      -25-
<PAGE>

     The Rights Agent shall be protected  and shall incur no liability for or in
respect of any action taken,  suffered or omitted by it in  connection  with its
administration  of this  Agreement  in reliance  upon any Right  Certificate  or
certificate for the Preferred Shares or Common Shares or for other securities of
the  Company,   instrument  of  assignment  or  transfer,   power  of  attorney,
endorsement,   affidavit,  letter,  notice,  instruction,   direction,  consent,
certificate,  statement, or other paper or document believed by it to be genuine
and to be signed,  executed and, where necessary,  verified or acknowledged,  by
the proper person or persons or otherwise  upon the advice of its counsel as set
forth in Section 20 hereof.

     Section 19. Merger or Consolidation or Change of Name  of Rights Agent. Any
corporation  or limited  liability  company  into which the Rights  Agent or any
successor  Rights Agent may be merged or with which it may be  consolidated,  or
any  corporation  or  limited  liability  company  resulting  from any merger or
consolidation to which the Rights Agent or any successor Rights Agent shall be a
party,  or any  corporation  or  limited  liability  company  succeeding  to the
corporate  trust  business of the Rights Agent or any  successor  Rights  Agent,
shall be the  successor  to the Rights  Agent under this  Agreement  without the
execution  or filing of any paper or any  further  act on the part of any of the
parties  hereto,  provided that such  corporation or limited  liability  company
would be  eligible  for  appointment  as a  successor  Rights  Agent  under  the
provisions of Section 21 hereof. In case at the time such successor Rights Agent
shall  succeed  to the  agency  created  by this  Agreement,  any of the  Rights
Certificates shall have been countersigned but not delivered, any such successor
Rights Agent may adopt the  countersignature of the predecessor Rights Agent and
deliver such Right  Certificates so countersigned;  and in case at that time any
of the  Right  Certificates  shall not have been  countersigned,  any  successor
Rights Agent may countersign such Right  Certificates  either in the name of the
predecessor  Rights Agent or in the name of the successor  Rights Agent;  and in
all such cases such Right Certificates shall have the full force provided in the
Right Certificates and in this Agreement.

     In case at any time the name of the Rights  Agent  shall be changed  and at
such time any of the Right  Certificates  shall have been  countersigned but not
delivered,  the Rights Agent may adopt the countersignature under its prior name
and deliver Right Certificates so countersigned; and in case at that time any of
the Right Certificates shall not have been counter- signed, the Rights Agent may
countersign such Right  Certificates  either in its prior name or in its changed
name;  and in all such cases such Right  Certificates  shall have the full force
provided in the Right Certificates and in this Agreement.

     Section 20. Duties of Rights Agent.  The Rights Agent undertakes the duties
and  obligations  imposed  by  this  Agreement  upon  the  following  terms  and
conditions,  by all of which the Company and the holders of Right  Certificates,
by their acceptance thereof, shall be bound:

                                      -26-
<PAGE>

     (a) The  Rights  Agent may  consult  with legal  counsel  (who may be legal
counsel  for the  Company),  and the opinion of such  counsel  shall be full and
complete authorization and protection to the Rights Agent as to any action taken
or omitted by it in good faith and in accordance with such opinion.

     (b)  Whenever in the  performance  of its duties under this  Agreement  the
Rights Agent shall deem it  necessary  or  desirable  that any fact or matter be
proved or  established  by the Company  prior to taking or suffering  any action
hereunder,  the fact or matter  (unless  other  evidence  in respect  thereof be
herein  specifically  prescribed)  may be deemed to be  conclusively  proved and
established by a certificate signed by any one of the Chairman of the Board, the
President, any Vice President, the Treasurer or the Secretary of the Company and
delivered to the Rights Agent; and the certificate  shall be full  authorization
to the Rights  Agent for any action  taken or suffered in good faith by it under
the provisions of this Agreement in reliance upon the certificate.

     (c) The Rights Agent shall be liable hereunder only for its own negligence,
bad faith or willful misconduct.

     (d) The  Rights  Agent  shall not be liable  for or by reason of any of the
statements  of fact or  recitals  contained  in this  Agreement  or in the Right
Certificates (except its countersignature  thereof) or be required to verify the
same, but all such  statements and recitals are and shall be deemed to have been
made by the Company only.

     (e) The Rights  Agent shall not be under any  responsibility  in respect of
the validity of this Agreement or the execution and delivery  hereof (except the
due  execution  hereof by the Rights  Agent) or in respect  of the  validity  or
execution of any Right Certificate (except its  countersignature  thereof);  nor
shall it be  responsible  for any  breach  by the  Company  of any  covenant  or
condition contained in this Agreement or in any Right Certificate;  nor shall it
be responsible  for any adjustment  required under the provisions of Sections 3,
11,  13 or 24 or  responsible  for the  manner,  method  or  amount  of any such
adjustment or the  ascertaining of the existence of facts that would require any
such  adjustment  (except with  respect to the  exercise of Rights  evidenced by
Right Certificates after actual notice of any such adjustment);  nor shall it by
any act  hereunder  be deemed to make any  representation  or warranty as to the
authorization  or reservation of any Preferred  Shares to be issued  pursuant to
this Agreement or any Right  Certificate  or as to whether any Preferred  Shares
will,  when  issued,   be  validly   authorized  and  issued,   fully  paid  and
nonassessable.

     (f) The  Company  agrees that it will  perform,  execute,  acknowledge  and
deliver or cause to be performed, executed,  acknowledged and delivered all such
further and other acts, instruments and assurances as may reasonably be required
by the Rights Agent for the carrying  out or  performing  by the Rights Agent of
the provisions of this Agreement.

                                      -27-
<PAGE>

     (g)  The  Rights  Agent  is  hereby   authorized  and  directed  to  accept
instructions  with respect to the  performance of its duties  hereunder from any
one of the  Chairman  of the  Board,  the  President,  any Vice  President,  the
Secretary or the  Treasurer of the  Company,  and to apply to such  officers for
advice or instructions in connection with its duties, and it shall not be liable
for any action  taken or suffered to be taken by it in good faith in  accordance
with  instructions  from any of such officers.  At any time the Rights Agent may
apply to the Company for written instructions with respect to any matter arising
in connection with the Rights Agent's duties and obligations  arising under this
Rights Agreement.  Such application by the Rights Agent for written instructions
from the Company  may, at the option of the Rights  Agent,  set forth in writing
any action  proposed to be taken or omitted by the Rights  Agent with respect to
its duties or  obligations  under this Rights  Agreement  and the date on and/or
after which such action  shall be taken and the Rights Agent shall not be liable
for any action taken or omitted in  accordance  with a proposal  included in any
such application on or after the date specified therein (which date shall be not
less than one business day after the Company receives such application,  without
the Company's consent) unless,  prior to taking or omitting any such action, the
Rights Agent has received  written  instructions in response to such application
specifying the action to be taken or omitted.

     (h) The Rights Agent and any shareholder,  director, officer or employee of
the Rights Agent may buy, sell or deal in any of the Rights or other  securities
of the Company or become pecuniarily  interested in any transaction in which the
Company  may be  interested,  or  contract  with or lend money to the Company or
otherwise  act as fully and freely as though it were not Rights Agent under this
Agreement.  Nothing  herein  shall  preclude the Rights Agent from acting in any
other capacity for the Company or for any other legal entity.

     (i) The Rights  Agent may execute and  exercise any of the rights or powers
hereby vested in it or perform any duty hereunder either itself or by or through
its  attorneys  or  agents,  and the Rights  Agent  shall not be  answerable  or
accountable for any act, default, neglect or misconduct of any such attorneys or
agents or for any loss to the  Company  resulting  from any such  act,  default,
neglect or misconduct,  provided  reasonable care was exercised in the selection
and continued employment thereof.

     (j) If, with respect to any Rights  Certificate  surrendered  to the Rights
Agent  for  exercise  or  transfer,  the  certificate  contained  in the form of
assignment or the form of election to purchase set forth on the reverse thereof,
as the case may be,  has not been  completed  to  certify  the  holder is not an
Acquiring Person (or an Affiliate or Associate thereof),  the Rights Agent shall
not take any further action with respect to such requested  exercise or transfer
without first consulting with the Company.

                                      -28-
<PAGE>

     Section  21.  Change of Rights Agent.  The  Rights  Agent or any  successor
Rights Agent may resign and be discharged  from its duties under this  Agreement
upon 30 days' notice in writing mailed to the Company and to each transfer agent
of the Common Shares and Preferred  Shares by registered or certified  mail, and
to the holders of the Right  Certificates  by first-class  mail. The Company may
remove the Rights  Agent or any  successor  Rights Agent upon 30 days' notice in
writing,  mailed to the Rights Agent or successor  Rights Agent, as the case may
be, and to each  transfer  agent of the Common  Shares and  Preferred  Shares by
registered or certified  mail, and to the holders of the Right  Certificates  by
first-class  mail.  If the  Rights  Agent  shall  resign or be  removed or shall
otherwise become  incapable of acting,  the Company shall appoint a successor to
the Rights  Agent.  If the Company shall fail to make the  appointment  within a
period  of 30 days  after  giving  notice of such  removal  or after it has been
notified  in writing of such  resignation  or  incapacity  by the  resigning  or
incapacitated  Rights Agent or by the holder of a Right  Certificate (who shall,
with the notice,  submit his Right  Certificate  for inspection by the Company),
then the Company shall become the Rights Agent, and the registered holder of any
Right  Certificate  may apply to any  court of  competent  jurisdiction  for the
appointment of a new Rights Agent. Any successor Rights Agent, whether appointed
by the  Company or by a court,  shall be a  corporation  or a limited  liability
company,  or an affiliate of such a corporation  or limited  liability  company,
organized  and  doing  business  under the laws of the  United  States or of the
States of Maryland  or New York (or of any other  state of the United  States so
long as such  corporation is authorized to do business as a banking  institution
in the States of Maryland or New York),  in good  standing,  that is  authorized
under  those  laws  to  exercise  corporate  trust  powers  and  is  subject  to
supervision or examination by federal or state  authorities  and that has at the
time of its  appointment  as Rights  Agent a combined  capital and surplus of at
least $50 million. After appointment, the successor Rights Agent shall be vested
with the same  powers,  rights,  duties and  responsibilities  as if it had been
originally  named  as  Rights  Agent  without  further  act  or  deed;  but  the
predecessor  Rights  Agent shall  deliver and transfer to the  successor  Rights
Agent any property at the time held by it hereunder, and execute and deliver any
further assurance,  conveyance, act or deed necessary for the purpose. Not later
than the effective  date of any such  appointment  the Company shall file notice
thereof in writing with the predecessor  Rights Agent and each transfer agent of
the Common Shares and Preferred Shares,  and mail a notice thereof in writing to
the  registered  holders of the Right  Certificates.  Failure to give any notice
provided  for in this  Section 21,  however,  or any defect  therein,  shall not
affect the  legality  or validity  of the  resignation  or removal of the Rights
Agent or the appointment of the successor Rights Agent, as the case may be.

     Section 22. Issuance of New Right Certificates.  Notwithstanding any of the
provisions of this Agreement or of the Rights to the contrary,  the Company may,
at its option,  issue new Right  Certificates  evidencing Rights in such form as
may be approved by a majority of the Board to reflect any  adjustment  or change
in the  Purchase  Price  and the  number  or kind or  class of  shares  or other
securities  or  property  purchasable  under  the  Right  Certificates  made  in
accordance  with the provisions of this  Agreement.  In addition,  in connection
with the issuance or sale of Common Shares following the  Distribution  Date and
prior to the earlier of the Redemption Date and the Expiration Date, the Company
may with respect to Common Shares so issued or sold pursuant to (i) the exercise
of stock  options;  (ii) any employee plan or  arrangement,  (iii) the exercise,

                                      -29-
<PAGE>

conversion or exchange of notes,  debentures or other  securities  issued by the
Company or (iv) any other  contractual  obligation of the Company,  in each case
existing prior to the Distribution Date, issue Right  Certificates  representing
the appropriate number of Rights in connection with such issuance or sale.

     Section 23.  Redemption.  (a) The Board of Directors of the Company may, at
its option, at any time prior to the earlier of (i) the close of business on the
Share  Acquisition  Date (or, if the Share  Acquisition Date shall have occurred
prior to the Effective  Date, the close of business on the Effective  Date),  or
(ii) the  Final  Expiration  Date,  redeem  all but not  less  than all the then
outstanding  Rights at a redemption price of $.001 per Right, as such amount may
be appropriately  adjusted to reflect any stock split, stock dividend or similar
transaction  occurring  after  the date  hereof  (such  redemption  price  being
hereinafter referred to as the "Redemption Price"). The redemption of the Rights
may be made  effective  at such times and with such  conditions  as the Board of
Directors  in  its  sole  discretion  may  establish.  Notwithstanding  anything
contained  in  this  Agreement  to  the  contrary,   the  Rights  shall  not  be
exercisable,  and a Triggering Event shall not be deemed to have occurred, until
such time as the Company's right of redemption hereunder has expired.

     (b)  Immediately  upon the action of the Board of  Directors of the Company
ordering  the  redemption  of the  Rights  (or such  later  time as the Board of
Directors may establish for the effectiveness of such  redemption),  and without
any further action and without any notice, the right to exercise the Rights will
terminate  and the only right  thereafter  of the holders of Rights  shall be to
receive the Redemption  Price.  The Company shall promptly give public notice of
any such redemption;  provided, however, that the failure to give, or any defect
in, any such notice shall not affect the validity of such redemption.  Within 10
days after the action of the Board of Directors  ordering the  redemption of the
Rights, the Company shall mail a notice of redemption to the holders of the then
outstanding  Rights by  mailing  the  notice to all such  holders  at their last
addresses as they appear upon the  registry  books of the Rights Agent or, prior
to the  Distribution  Date, on the registry  books of the transfer agent for the
Common  Shares and  Preferred  Shares.  Any notice which is mailed in the manner
herein  provided shall be deemed given,  whether or not the holder  receives the
notice.  Each  such  notice of  redemption  will  state the  method by which the
payment of the Redemption Price will be made. In any case,  failure to give such
notice by mail, or any defect in the notice,  to any particular holder of Rights
shall not affect the sufficiency of the notice to other holders of Rights.


     Section 24. Notice of Certain Events.  In case the Company shall propose at
any time  following  the  Distribution  Date (a) to pay any dividend  payable in
stock of any class to the holders of the  Preferred  Shares or to make any other
distribution  to the  holders  of the  Preferred  Shares  (other  than a regular
quarterly cash dividend) or (b) to offer to the holders of its Preferred  Shares
rights or warrants to  subscribe  for or to purchase  any  additional  Preferred

                                      -30-
<PAGE>

Shares  or  shares  of stock of any  class or any  other  securities,  rights or
options,  or (c) to effect any  reclassification  of its Preferred Shares (other
than a reclassification  involving only the subdivision of outstanding Preferred
Shares),  (d) to effect any  consolidation,  merger or statutory  share exchange
into or with, or to effect any sale or other  transfer (or to permit one or more
of its  Subsidiaries  to  effect  any  sale or other  transfer),  in one or more
transactions,  of 50% or more of the assets or earning  power of the Company and
its  Subsidiaries  (taken as a whole) to any other  Person or (e) to effect  the
liquidation,  dissolution or winding up of the Company, then, in each such case,
the Company shall give to each holder of a Right,  in accordance with Section 25
hereof,  a notice of such proposed  action,  which shall specify the record date
for the purposes of such stock dividend,  or distribution of rights or warrants,
or the date on which such  reclassification,  consolidation,  merger,  statutory
share exchange, sale, transfer,  liquidation,  dissolution,  or winding up is to
take place and the date of participation therein by the holders of the Preferred
Shares, if any such date is to be fixed, and the notice shall be so given in the
case of any action  covered by clause (a) or (b) above at least 10 days prior to
the record date for  determining  holders of the Common Shares and/or  Preferred
Shares for purposes of such action, and in the case of any such other action, at
least 10 days  prior to the date of the  taking of such  proposed  action or the
date of  participation  therein by the holders of the Common  Shares,  whichever
shall be the earlier.  The failure to give notice required by this Section 24 or
any defect therein shall not affect the legality or validity of the action taken
by the Company or the vote upon any such action.

     In case any of the events set forth in  Section  11(a)(ii)  or 13 hereof of
this Agreement shall occur, then, in any such case, the Company shall as soon as
practicable  thereafter give to each holder of a Right (or if occurring prior to
the Distribution Date, the holders of Common Shares), in accordance with Section
25 hereof,  a notice of the  occurrence  of such event,  which shall specify the
event and the  consequences  of the event to  holders  of Rights  under  Section
11(a)(ii) or 13 hereof,  as the case may be, and all  references in this Section
24 to Preferred  Shares shall be deemed  thereafter to refer to Common Shares or
other capital stock, as the case may be.

     Section 25. Notices.  Notices or demands authorized by this Agreement to be
given or made by the Rights Agent or by the holder of any Right  Certificate  to
or on the Company  shall be  sufficiently  given or made if sent by  first-class
mail, postage prepaid, addressed (until another address is filed in writing with
the Rights Agent) as follows:

                      Human  Genome  Sciences,  Inc.  
                      9410 Key West Avenue
                      Rockville,  MD 20850 (301)
                      309-8439 (fax) Attention: Corporate Secretary


                                      -31-

<PAGE>

Subject to the provisions of Section 21 hereof,  any notice or demand authorized
by this  Agreement  to be given or made by the  Company  or by the holder of any
Right Certificate to or on the Rights Agent shall be sufficiently  given or made
if sent by first-class mail,  postage prepaid,  addressed (until another address
is filed in writing with the Company) as follows:

                      American Stock Transfer & Trust Company
                      40 Wall Street
                      New York, NY 10005
                      Attn:  Corporate Trust Department
                      Fax: (718) 236-4558

Notices  or  demands  authorized  by this  Agreement  to be given or made by the
Company or the  Rights  Agent to the  holder of any Right  Certificate  shall be
sufficiently  given  or  made  if sent by  first-class  mail,  postage  prepaid,
addressed  to the holder at the  address of the holder as shown on the  registry
books of the Company.
          
     Section 26. Supplements and Amendments. Prior to the Distribution Date, and
subject to the  penultimate  sentence  of this  Section  26, the Company and the
Rights Agent shall, if the Company so directs, supplement or amend any provision
of  this  Agreement,  without  the  approval  of  any  holders  of  certificates
representing Common Shares,  including,  without  limitation,  any supplement or
amendment  deemed  necessary  or  appropriate  by the  Company  in  light of any
judicial or other legal  developments,  whether or not controlling  precedent in
respect of this Agreement.  From and after the Distribution  Date and subject to
the  penultimate  sentence of this  Section 26, the Company and the Rights Agent
shall, if the Company so directs, supplement or amend this Agreement without the
approval  of any  holders  of  Rights  Certificates  in  order  (i) to cure  any
ambiguity,  (ii) to correct or supplement any provision  contained  herein which
may be defective or  inconsistent  with any other  provisions  herein,  (iii) to
shorten or lengthen any time period  hereunder,  or (iv) to change or supplement
the  provisions  hereunder in any manner which the Company may deem necessary or
desirable and which shall not  adversely  affect the interests of the holders of
Rights Certificates (other than an Acquiring Person or an Affiliate or Associate
of  any  Acquiring  Person);  provided;  however,  this  Agreement  may  not  be
supplemented or amended to lengthen,  pursuant to clause (iii) of this sentence,
(A) a time  period  relating  to when the Rights may be redeemed at such time as
the Rights are not then  redeemable,  or (B) any other time  period  unless such
lengthening is for the purpose of protecting, enhancing or clarifying the rights
of,  and/or the  benefits  to,  the  holders of  Rights.  Without  limiting  the
foregoing,  the Company may at any time prior to such time as any Person becomes
an Acquiring  Person amend this  Agreement to lower the  thresholds set forth in
Section  1(a)  and  3(a)  hereof  from  15% (or  20.0%  in the  case of the Bass

                                      -32-
<PAGE>

Investors)  to any  percentage  greater  than  the  greater  of (i) the  largest
percentage  of the  outstanding  Common  Shares  then known by the Company to be
beneficially  owned by any Person  (other  than the  Company,  any  wholly-owned
Subsidiary  of the Company,  any employee  benefit plan of the Company or of any
Subsidiary, any Person holding Common Shares for or pursuant to the terms of any
such plan or, except in the case of a lowering of the 20%  threshhold,  the Bass
Investors) and (ii) 10%.

     Upon the  delivery  of a  certificate  from an  appropriate  officer of the
Company which states that the proposed  supplement or amendment is in compliance
with  the  terms of this  Section  26,  the  Rights  Agent  shall  execute  such
supplement or amendment and shall be fully  protected by Section 18 in so doing.
Notwithstanding  anything  contained  in  this  Agreement  to the  contrary,  no
supplement or amendment  shall be made at any time which changes the  Redemption
Price or the  number of Common  Shares for which a Right is  exercisable  and no
supplement or amendment shall be made after the Distribution  Date which changes
the Final Expiration Date to a date earlier than the tenth (10th) anniversary of
the Effective Date. Prior to the Distribution  Date, the interest of the holders
of Rights shall be deemed coincident with the interests of the holders of Common
Shares.

     Section 27. Exchange. (a) Subject to any limitations of applicable law, the
Board of  Directors  of the Company  may,  at its option,  at any time after any
person becomes an Acquiring Person, exchange all or part of the then outstanding
and  exercisable  Rights  (which shall not include  Rights that have become void
pursuant to the provisions of Section  11(a)(ii) hereof) for Common Shares at an
exchange ratio of one Common Share per Right,  appropriately adjusted to reflect
any stock split, stock dividend or similar transaction  occurring after the date
hereof  (such  exchange  ratio being  hereinafter  referred to as the  "Exchange
Ratio").  Notwithstanding  the  foregoing,  the Board of Directors  shall not be
empowered to effect such  exchange at any time after any Person  (other than the
Company,  any wholly-owned  Subsidiary of the Company, any employee benefit plan
of the Company or of any Subsidiary,  or any Person holding Common Shares for or
pursuant  to the  terms of any such  plan),  together  with all  Affiliates  and
Associates of such Person,  becomes the Beneficial Owner of more than 50% of the
Common Shares then outstanding.

     (b)  Immediately  upon the action of the Board of  Directors of the Company
ordering the exchange of any Rights  pursuant to subsection  (a) of this Section
27 and without any further action and without any notice,  the right to exercise
such Rights shall  terminate and the only rights  thereafter of a holder of such
Rights shall be to receive  that number of Common  Shares equal to the number of
such Rights held by such holder  multiplied by the Exchange  Ratio.  The Company
shall promptly give public notice of any such exchange;  provided, however, that

                                      -33-
<PAGE>

the failure to give, or any defect in, such notice shall not affect the validity
of such exchange.  The Company promptly shall mail a notice of any such exchange
to all of the holders of such Rights at their last addresses as they appear upon
the registry books of the Rights Agent. Any notice which is mailed in the manner
herein  provided shall be deemed given,  whether or not the holder  receives the
notice. Each such notice of exchange will state the method by which the exchange
of the Common  Shares  for  Rights  will be  effected  and,  in the event of any
partial  exchange,  the number of Rights  which will be  exchanged.  Any partial
exchange  shall be effected  pro rata based on the number of Rights  (other than
Rights which have become void pursuant to the  provisions  of Section  11(a)(ii)
hereof) held by each holder of Rights.

     (c) In any  exchange  pursuant  to this  Section  27, the  Company,  at its
option,  may  substitute  Preferred  Shares or equivalent  preferred  shares for
Common Shares exchangeable for Rights, at the initial rate of one one-thousandth
of a Preferred Share (or an appropriate  number of equivalent  preferred shares)
for each Common Share, as appropriately  adjusted to reflect  adjustments in the
voting rights of the Preferred Shares pursuant to the terms thereof, so that the
fraction of a Preferred  Share delivered in lieu of each Common Share shall have
the same voting rights as one Common Share.

     (d) In  the  event  that  there  shall  not be  sufficient  Common  Shares,
Preferred  Shares or equivalent  preferred  shares issued but not outstanding or
authorized  but  unissued to permit any  exchange of Rights as  contemplated  in
accordance  with this Section 27, the Company  shall take all such action as may
be necessary to authorize additional Common Shares for issuance upon exchange of
the Rights.

     (e) The Company  shall not be required to issue  fractions of Common Shares
or to distribute  certificates which evidence  fractional Common Shares. In lieu
of such fractional Common Shares, the Company shall pay to the registered holder
of the Right  Certificates  with regard to which such  fractional  Common Shares
would  otherwise be issuable an amount in cash equal to the same fraction of the
current  market  value  of a  whole  Common  Share.  For  the  purposes  of this
subsection  (d),  the current  market value of a whole Common Share shall be the
closing price of a Common Share (as determined pursuant to Section 11(d) hereof)
for the Trading Day  immediately  after the public  announcement  by the Company
that an exchange is to be effected pursuant to this Section 27.

     Section 28. Successors.  All the covenants and provisions of this Agreement
by or for the benefit of the Company or the Rights Agent shall bind and inure to
the benefit of their respective successors and assigns hereunder.

                                      -34-
<PAGE>

     Section 29. Determinations and Actions by the Board of  Directors, etc. For
all purposes of this Agreement,  except as explicitly otherwise provided in this
Agreement,  the Board of Directors of the Company shall have the exclusive power
and authority to administer this Agreement and to exercise all rights and powers
specifically  granted to the Board or to the Company,  or as may be necessary or
advisable  in  the   administration  of  this  Agreement,   including,   without
limitation,  the  right  and  power  to (i)  interpret  the  provisions  of this
Agreement,  and (ii) make all  determinations  deemed necessary or advisable for
the administration of this Agreement (including a determination to redeem or not
redeem the Rights or to amend the  Agreement).  All such actions,  calculations,
interpretations and determinations (including, for purposes of clause (y) below,
all omissions with respect to the foregoing) which are done or made by the Board
in good faith,  shall (x) be final,  conclusive and binding on the Company,  the
Rights  Agent,  the  holders of the Rights  and all other  parties,  and (y) not
subject the Board to any liability to the holders of the Rights.

     Section 30. Benefits of this Agreement.  Nothing in this Agreement shall be
construed to give to any Person other than the Company, the Rights Agent and the
registered  holders of the Right  Certificates  (and,  prior to the Distribution
Date,  the Common  Shares) any legal or equitable  right,  remedy or claim under
this Agreement;  but this Agreement shall be for the sole and exclusive  benefit
of the  Company,  the  Rights  Agent  and the  registered  holders  of the Right
Certificates (and, prior to the Distribution Date, the Common Shares).

     Section 31. Severability.  If any term, provision,  covenant or restriction
of this  Agreement  is  held  by a court  of  competent  jurisdiction  or  other
authority  to be invalid,  void or  unenforceable,  the  remainder of the terms,
provisions,  covenants and  restrictions  of this Agreement shall remain in full
force and  effect  and shall in no way be  affected,  impaired  or  invalidated.
Section 32.  Governing Law.  This  Agreement and each Right  Certificate  issued
hereunder  shall be deemed to be a contract  made under the laws of the State of
Delaware and for all purposes  shall be governed by and  construed in accordance
with the laws of such State  applicable  to contracts  to be made and  performed
entirely within such State.

     Section 33.  Counterparts.  This Agreement may be executed in any number of
counterparts and each of such  counterparts  shall for all purposes be deemed to
be an original,  and all such counterparts shall together constitute but one and
the same instrument.

     Section  34.  Descriptive Headings.  Descriptive  headings  of the  several
Sections of this  Agreement  are  inserted  for  convenience  only and shall not
control or affect the meaning or construction of any of the provisions hereof.

                                      -35-
<PAGE>

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Agreement to be
duly executed and their  respective  corporate seals to be hereunto  affixed and
attested, all as of the day and year first above written.

                                 HUMAN GENOME SCIENCES, INC.
Attest:


By /s/ James H. Davis            By /s/ William A. Haseltine                    
   ----------------------           --------------------------------------------
   Title: Assistant Secretary       Name:   William A. Haseltine, Ph.D.
                                    Title:  Chairman and Chief Executive Officer


                                  AMERICAN STOCK TRANSFER &
                                  TRUST COMPANY
Attest:



By /s/ Susan Silber               By /s/ Herbert J. Lemmer                      
   ----------------------------      -------------------------------------------
   Title:  Assistant Secretary       Name: Herbert J. Lemmer
                                     Title: Vice President














                                      -36-

<PAGE>
                         
                                                                      EXHIBIT A

                   CERTIFICATE OF DESIGNATION, PREFERENCES AND
             RIGHTS OF SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                       of

                           HUMAN GENOME SCIENCES, INC.

             Pursuant to Section 151 of the General Corporation Law
                            of the State of Delaware


     We, William A. Haseltine,  Ph.D., Chairman of the Board and Chief Executive
Officer,  and James H. Davis, Ph.D., Senior Vice President,  General Counsel and
Secretary, of Human Genome Sciences,  Inc., a corporation organized and existing
under the General  Corporation Law of the State of Delaware,  in accordance with
the provisions of Section 103 thereof, DO HEREBY CERTIFY:

     That pursuant to the authority conferred upon the Board of Directors by the
Restated Certificate of Incorporation,  as amended, of the said Corporation, the
said  Board of  Directors  on May 20,  1998  adopted  the  following  resolution
creating a series of 30,000  shares of Preferred  Stock  designated  as Series A
Junior Participating Preferred Stock:

     RESOLVED,  that pursuant to the authority  vested in the Board of Directors
of this  Corporation  in accordance  with the  provisions of its  Certificate of
Incorporation, as amended, a series of Preferred Stock of the Corporation be and
it hereby is created, and that the designation and amount thereof and the voting
powers,  preferences  and  relative,  participating,  optional and other special
rights of the shares of such series,  and the  qualifications,  limitations  and
restrictions thereof are as follows:

     Section 1.  Designation  and  Amount.  The shares of such  series  shall be
designated as "Series A Junior Participating  Preferred Stock" and the number of
shares constituting such series shall be 30,000.

         Section 2.        Dividends and Distributions.

     (A) Subject to the prior and  superior  rights of the holders of any shares
of any series of  Preferred  Stock  ranking  prior and superior to the shares of
Series A Junior  Participating  Preferred  Stock with respect to dividends,  the
holders  of shares of Series A Junior  Participating  Preferred  Stock  shall be
entitled to receive,  when,  as and if declared by the Board of Directors out of
funds legally available for the purpose,  quarterly dividends payable in cash on
the first day of January,  April,  July and October in each year (each such date
being referred to herein as a "Quarterly Dividend Payment Date"),  commencing on

                                      A-1

<PAGE>

the first Quarterly Dividend Payment Date after the first issuance of a share or
fraction  of a share of Series A Junior  Participating  Preferred  Stock,  in an
amount per share  (rounded  to the  nearest  cent)  equal to the  greater of (a)
$45.00 or (b) subject to the provision  for  adjustment  hereinafter  set forth,
1,000 times the  aggregate  per share  amount of all cash  dividends,  and 1,000
times the aggregate per share amount (payable in kind) of all non-cash dividends
or other  distributions  other than a dividend payable in shares of Common Stock
or a subdivision of the outstanding shares of Common Stock (by  reclassification
or  otherwise),  declared  on  the  Common  Stock,  without  par  value,  of the
Corporation  (the "Common  Stock")  since the  immediately  preceding  Quarterly
Dividend Payment Date, or, with respect to the first Quarterly  Dividend Payment
Date,  since the first  issuance of any share or fraction of a share of Series A
Junior Participating  Preferred Stock. In the event the Corporation shall at any
time after June 20, 1998 (the  "Effective  Date") (i)  declare  any  dividend on
Common Stock payable in shares of Common Stock,  (ii) subdivide the  outstanding
Common  Stock,  or (iii)  combine the  outstanding  Common  Stock into a smaller
number of shares,  then in each such case the amount to which  holders of shares
of Series A Junior Participating Preferred Stock were entitled immediately prior
to such event under clause (b) of the  preceding  sentence  shall be adjusted by
multiplying  such amount by a fraction  the  numerator of which is the number of
shares  of  Common  Stock  outstanding  immediately  after  such  event  and the
denominator  of  which is the  number  of  shares  of  Common  Stock  that  were
outstanding immediately prior to such event.

     (B) The Corporation  shall declare a dividend or distribution on the Series
A Junior  Participating  Preferred  Stock as  provided  in  paragraph  (A) above
immediately  after it declares a dividend or  distribution  on the Common  Stock
(other than a dividend  payable in shares of Common Stock);  provided,  however,
that, in the event no dividend or  distribution  shall have been declared on the
Common Stock during the period between any Quarterly  Dividend  Payment Date and
the next subsequent  Quarterly  Dividend  Payment Date, a dividend of $45.00 per
shall on the Series A Junior Participating Preferred Stock shall nevertheless be
payable on such subsequent Quarterly Dividend Payment Date.

     (C) Dividends shall begin to accrue and be cumulative on outstanding shares
of Series A Junior  Participating  Preferred  Stock from the Quarterly  Dividend
Payment Date next  preceding the date of issue of such shares of Series A Junior
Participating  Preferred Stock, unless the date of issue of such shares is prior
to the record date for the first Quarterly  Dividend Payment Date, in which case
dividends  on such  shares  shall begin to accrue from the date of issue of such
shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a
date after the record date for the  determination of holders of shares of Series
A Junior Participating  Preferred Stock entitled to receive a quarterly dividend
and before such Quarterly  Dividend Payment Date, in either of which events such
dividends shall begin to accrue and be cumulative  from such Quarterly  Dividend
Payment Date.  Accrued but unpaid  dividends shall not bear interest.  Dividends
paid on the shares of Series A Junior Participating Preferred Stock in an amount
less than the total amount of such  dividends at the time accrued and payable on

                                      A-2
<PAGE>


such shares shall be allocated pro rata on a share-by-share basis among all such
shares at the time outstanding. The Board of Directors may fix a record date for
the  determination  of  holders  of  shares  of  Series A  Junior  Participating
Preferred  Stock  entitled  to receive  payment of a  dividend  or  distribution
declared thereon, which record date shall be no more than thirty (30) days prior
to the date fixed for the payment thereof.

     Section  3.  Voting  Rights.  The  holders  of  shares  of  Series A Junior
Participating Preferred Stock shall have the following voting rights:

     (A) Subject to the provision for  adjustment  hereinafter  set forth,  each
share of Series A Junior Participating  Preferred Stock shall entitle the holder
thereof to 1,000 votes on all matters submitted to a vote of the stockholders of
the Corporation. In the event the Corporation shall at any time after the Rights
Declaration  Date (i) declare any dividend on Common Stock  payable in shares of
Common Stock, (ii) subdivide the outstanding  Common Stock, or (iii) combine the
outstanding Common Stock into a smaller number of shares, then in each such case
the  number  of votes per  share to which  holders  of shares of Series A Junior
Participating  Preferred  Stock were  entitled  immediately  prior to such event
shall be adjusted by  multiplying  such number by a fraction  the  numerator  of
which is the number of shares of Common Stock outstanding immediately after such
event and the  denominator of which is the number of shares of Common Stock that
were outstanding immediately prior to such event.

     (B) Except as otherwise provided herein or by law, the holders of shares of
Series A Junior  Participating  Preferred  Stock  and the  holders  of shares of
Common Stock shall vote together as one class on all matters submitted to a vote
of stockholders of the Corporation.

     (C) (i) If at any time  dividends  on any  Series  A  Junior  Participating
Preferred  Stock  shall be in  arrears in an amount  equal to six (6)  quarterly
dividends  thereon,  the occurrence of such contingency shall mark the beginning
of a period  (herein  called a "default  period")  which shall extend until such
time when all accrued and unpaid dividends for all previous  quarterly  dividend
periods and for the current quarterly  dividend period on all shares of Series A
Junior  Participating  Preferred Stock then outstanding shall have been declared
and paid or set apart for payment.  During each default  period,  all holders of
Preferred  Stock  (including  holders  of  the  Series  A  Junior  Participating
Preferred  Stock)  with  dividends  in  arrears  in an  amount  equal to six (6)
quarterly dividends thereon,  voting as a class,  irrespective of series,  shall
have the right to elect two (2) Directors.

     (ii) During any default period,  such voting right of the holders of Series
A Junior  Participating  Preferred Stock may be exercised initially at a special
meeting  called  pursuant to  subparagraph  (iii) of this Section 3(C) or at any
annual  meeting  of   stockholders,   and  thereafter  at  annual   meetings  of
stockholders,  provided  that  neither  such  voting  right nor the right of the
holders of any other series of Preferred Stock, if any, to increase,  in certain
cases, the authorized  number of Directors shall be exercised unless the holders
of ten percent (10%) in number of shares of Preferred Stock outstanding shall be

                                      A-3
<PAGE>

present in person or by proxy.  The absence of a quorum of the holders of Common
Stock shall not affect the  exercise by the holders of  Preferred  Stock of such
voting  right.  At any  meeting at which the  holders of  Preferred  Stock shall
exercise such voting right initially  during an existing  default  period,  they
shall  have the  right,  voting  as a class,  to elect  Directors  to fill  such
vacancies,  if any,  in the Board of  Directors  as may then exist up to two (2)
Directors or, if such right is exercised at an annual meeting,  to elect two (2)
Directors. If the number which may be so elected at any special meeting does not
amount to the required number, the holders of the Preferred Stock shall have the
right to make such  increase in the number of Directors as shall be necessary to
permit the  election by them of the  required  number.  After the holders of the
Preferred  Stock  shall have  exercised  their right to elect  Directors  in any
default  period  and  during  the  continuance  of such  period,  the  number of
Directors  shall not be increased or decreased  except by vote of the holders of
Preferred  Stock as herein  provided  or  pursuant  to the  rights of any equity
securities   ranking   senior  to  or  pari  passu  with  the  Series  A  Junior
Participating Preferred Stock.

     (iii)  Unless the  holders of  Preferred  Stock  shall,  during an existing
default period,  have previously  exercised their right to elect Directors,  the
Board of Directors may order, or any  stockholder or stockholders  owning in the
aggregate  not less  than ten  percent  (10%) of the  total  number of shares of
Preferred Stock outstanding, irrespective of series, may request, the calling of
a special  meeting of the  holders  of  Preferred  Stock,  which  meeting  shall
thereupon be called by the President,  a Vice-President  or the Secretary of the
Corporation.  Notice of such meeting and of any annual  meeting at which holders
of Preferred  Stock are  entitled to vote  pursuant to this  paragraph  (C)(iii)
shall be given to each holder of record of Preferred  Stock by mailing a copy of
such notice to him at his last  address as the same  appears on the books of the
Corporation.  Such  meeting  shall be called for a time not earlier  than twenty
(20) days and not later  than  sixty (60) days after such order or request or in
default of the  calling of such  meeting  within  sixty (60) after such order or
request,  such  meeting may be called on similar  notice by any  stockholder  or
stockholders  owning in the  aggregate  not less than ten  percent  (10%) of the
total  number of shares of  Preferred  Stock  outstanding.  Notwithstanding  the
provisions of this paragraph  (C)(iii),  no such special meeting shall be called
during the period  within sixty (60) days  immediately  preceding the date fixed
for the next annual meeting of the stockholders.

     (iv) In any default period,  the holders of Common Stock, and other classes
of stock of the  Corporation  if  applicable,  shall  continue to be entitled to
elect the whole number of Directors  until the holders of Preferred  Stock shall
have exercised their right to elect two (2) Directors  voting as a class,  after
the  exercise  of which  right (x) the  Directors  so elected by the  holders of

                                      A-4
<PAGE>

Preferred Stock shall continue in office until their  successors shall have been
elected by such holders or until the expiration of the default  period,  and (y)
any vacancy in the Board of  Directors  may  (except as  provided  in  paragraph
(C)(ii)  of this  Section 3) be filled by vote of a  majority  of the  remaining
Directors theretofore elected by the holders of the class of stock which elected
the Director whose office shall have become vacant. References in this paragraph
(C) to  Directors  elected by the holders of a  particular  class of stock shall
include  Directors  elected by such  Directors to fill  vacancies as provided in
clause (y) of the foregoing sentence.

     (v) Immediately  upon the expiration of a default period,  (x) the right of
the holders of Preferred Stock as a class to elect  Directors  shall cease,  (y)
the term of any Directors  elected by the holders of Preferred  Stock as a class
shall terminate,  and (z) the number of Directors shall be such number as may be
provided for in the certificate of incorporation or by-laws  irrespective of any
increase made pursuant to the provisions of paragraph  (C)(ii) of this Section 3
(such number being subject, however, to change thereafter in any manner provided
by law or in the certificate of incorporation or by-laws).  Any vacancies in the
Board of  Directors  effected  by the  provisions  of clauses (y) and (z) in the
preceding sentence may be filled by a majority of the remaining Directors.

     (D) Except as set forth  herein,  holders of Series A Junior  Participating
Preferred  Stock shall have no special voting rights and their consent shall not
be  required  (except to the extent they are  entitled  to vote with  holders of
Common Stock as set forth herein) for taking any corporate action.

     Section 4. Certain Restrictions.

     (A)  Whenever  quarterly  dividends  or other  dividends  or  distributions
payable on the Series A Junior  Participating  Preferred  Stock as  provided  in
Section 2 are in arrears,  thereafter and until all accrued and unpaid dividends
and  distributions,  whether  or not  declared,  on  shares  of  Series A Junior
Participating  Preferred  Stock  outstanding  shall have been paid in full,  the
Corporation shall not:

     (i) declare or pay dividends on, make any other distributions on, or redeem
or purchase or otherwise  acquire for  consideration any shares of stock ranking
junior (either as to dividends or upon  liquidation,  dissolution or winding up)
to the Series A Junior Participating Preferred Stock;

     (ii)  declare or pay  dividends on or make any other  distributions  on any
shares of stock ranking on a parity (either as to dividends or upon liquidation,
dissolution  or  winding  up) with the Series A Junior  Participating  Preferred
Stock,  except  dividends  paid  ratably  on the  Series A Junior  Participating
Preferred  Stock and all such parity stock on which  dividends are payable or in
arrears in  proportion  to the total  amounts  to which the  holders of all such
shares are then entitled;

                                      A-5

<PAGE>

     (iii) redeem or purchase or otherwise acquire for  consideration  shares of
any stock  ranking on a parity  (either  as to  dividends  or upon  liquidation,
dissolution  or  winding  up) with the Series A Junior  Participating  Preferred
Stock,  provided  that the  Corporation  may at any  time  redeem,  purchase  or
otherwise  acquire shares of any such parity stock in exchange for shares of any
stock  of the  Corporation  ranking  junior  (either  as to  dividends  or  upon
dissolution,  liquidation  or winding  up) to the Series A Junior  Participating
Preferred Stock;

     (iv) purchase or otherwise acquire for consideration any shares of Series A
Junior Participating Preferred Stock, or any shares of stock ranking on a parity
with the Series A Junior  Participating  Preferred  Stock,  except in accordance
with a purchase  offer made in writing or by  publication  (as determined by the
Board of  Directors)  to all holders of such shares upon such terms as the Board
of Directors,  after  consideration of the respective  annual dividend rates and
other relative  rights and  preferences  of the  respective  series and classes,
shall determine in good faith will result in fair and equitable  treatment among
the respective series or classes.

     (B) The  Corporation  shall not permit any subsidiary of the Corporation to
purchase  or  otherwise  acquire  for  consideration  any shares of stock of the
Corporation unless the Corporation could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

     Section 5. Reacquired Shares.  Any shares of Series A Junior  Participating
Preferred Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever  shall be  retired  and  cancelled  promptly  after  the  acquisition
thereof.  All such shares shall upon their  cancellation  become  authorized but
unissued  shares of Preferred  Stock and may be reissued as part of a new series
of Preferred  Stock to be created by resolution or  resolutions  of the Board of
Directors,  subject to the  conditions  and  restrictions  on issuance set forth
herein.

     Section 6. Liquidation, Dissolution or Winding Up.

     (A) Upon any liquidation  (voluntary or otherwise),  dissolution or winding
up of the Corporation, no distribution shall be made to the holders of shares of
stock ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series A Junior  Participating  Preferred Stock unless, prior
thereto, the holders of shares of Series A Junior Participating  Preferred Stock
shall have  received  $250.00  per share,  plus an amount  equal to accrued  and
unpaid dividends and distributions thereon, whether or not declared, to the date
of such payment (the "Series A Liquidation  Preference").  Following the payment

                                      A-6

<PAGE>

of the  full  amount  of the  Series A  Liquidation  Preference,  no  additional
distributions  shall  be made to the  holders  of  shares  of  Series  A  Junior
Participating  Preferred Stock unless,  prior thereto,  the holders of shares of
Common Stock shall have  received an amount per share (the "Common  Adjustment")
equal  to the  quotient  obtained  by  dividing  (i) the  Series  A  Liquidation
Preference by (ii) 1,000 (as appropriately adjusted as set forth in subparagraph
C  below  to  reflect  such  events  as  stock  splits,   stock   dividends  and
recapitalizations with respect to the Common Stock) (such number in clause (ii),
the "Adjustment Number"). Following the payment of the full amount of the Series
A Liquidation Preference and the Common Adjustment in respect of all outstanding
shares of  Series A Junior  Participating  Preferred  Stock  and  Common  Stock,
respectively,  holders  of  Series A Junior  Participating  Preferred  Stock and
holders of shares of Common Stock shall receive their ratable and  proportionate
share of the remaining  assets to be  distributed in the ratio of the Adjustment
Number to 1 with  respect to such  Preferred  Stock and Common  Stock,  on a per
share basis, respectively.

     (B) In the event,  however,  that there are not sufficient assets available
to  permit  payment  in full of the  Series  A  Liquidation  Preference  and the
liquidation  preferences of all other series of preferred  stock,  if any, which
rank on a parity with the Series A Junior  Participating  Preferred Stock,  then
such remaining assets shall be distributed ratably to the holders of such parity
shares in proportion to their respective liquidation preferences.  In the event,
however,  that there are not  sufficient  assets  available to permit payment in
full of the Common  Adjustment,  then such remaining assets shall be distributed
ratably to the holders of Common Stock.

     (C) In the  event  the  Corporation  shall at any  time  after  the  Rights
Declaration  Date (i) declare any dividend on Common Stock  payable in shares of
Common Stock, (ii) subdivide the outstanding  Common Stock, or (iii) combine the
outstanding Common Stock into a smaller number of shares, then in each such case
the  Adjustment  Number  in  effect  immediately  prior to such  event  shall be
adjusted by multiplying  such  Adjustment  Number by a fraction the numerator of
which is the number of shares of Common Stock outstanding immediately after such
event and the  denominator of which is the number of shares of Common Stock that
were outstanding immediately prior to such event.

     Section 7. Consolidation,  Merger, etc. In case the Corporation shall enter
into any  consolidation,  merger,  combination or other transaction in which the
shares  of  Common  Stock are  exchanged  for or  changed  into  other  stock or
securities,  cash and/or any other property, then in any such case the shares of
Series  A  Junior  Participating  Preferred  Stock  shall  at the  same  time be
similarly  exchanged or changed in an amount per share (subject to the provision
for adjustment  hereinafter set forth) equal to 1,000 times the aggregate amount
of stock,  securities,  cash and/or any other property (payable in kind), as the

                                      A-7

<PAGE>

case may be,  into which or for which  each share of Common  Stock is changed or
exchanged.  In the  event the  Corporation  shall at any time  after the  Rights
Declaration  Date (i) declare any dividend on Common Stock  payable in shares of
Common Stock, (ii) subdivide the outstanding  Common Stock, or (iii) combine the
outstanding Common Stock into a smaller number of shares, then in each such case
the amount set forth in the  preceding  sentence with respect to the exchange or
change  of  shares of Series A Junior  Participating  Preferred  Stock  shall be
adjusted by multiplying  such amount by a fraction the numerator of which is the
number of shares of Common Stock  outstanding  immediately  after such event and
the  denominator  of which is the  number of shares  of Common  Stock  that were
outstanding immediately prior to such event.

     Section  8. No  Redemption.  The  shares of  Series A Junior  Participating
Preferred Stock shall not be redeemable.

     Section 9. Ranking. The Series A Junior Participating Preferred Stock shall
rank junior to all other series of the  Corporation's  Preferred Stock as to the
payment of dividends  and the  distribution  of assets,  unless the terms of any
such series shall provide otherwise.

     Section 10.  Amendment.  The  Restated  Certificate  of  Incorporation,  as
amended,  of the  Corporation  shall not be further  amended in any manner which
would  materially  alter or change the powers,  preferences or special rights of
the Series A Junior Participating Preferred Stock so as to affect them adversely
without  the  affirmative  vote  of the  holders  of a  majority  or more of the
outstanding  shares of Series A Junior  Participating  Preferred  Stock,  voting
separately as a class.

     Section 11.  Fractional  Shares.  Series A Junior  Participating  Preferred
Stock may be issued in fractions of a share which shall  entitle the holder,  in
proportion  to such  holder's  fractional  shares,  to exercise  voting  rights,
receive  dividends,  participate in distributions and to have the benefit of all
other rights of holders of Series A Junior Participating Preferred Stock.

     IN WITNESS WHEREOF, we have executed and subscribed this Certificate and do
affirm the  foregoing  as true under the  penalties  of perjury this 26th day of
May, 1998.



                                 ---------------------------------------        
                                 William A. Haseltine, Ph.D.
                                 Chairman of the Board and
                                   Chief Executive Officer





                                 ---------------------------------------        
                                 James H. Davis, Ph.D.
                                 Senior Vice President, General Counsel
                                   and Secretary








                                      A-8

<PAGE>


                                                                      Exhibit B
                                                                      ---------


                          [Form of Right Certificate]


Certificate No. R-                                        __________ Rights


           NOT  EXERCISABLE  AFTER  MAY 20, 2008 OR EARLIER IF
           NOTICE  OF REDEMPTION  IS  GIVEN.  THE  RIGHTS  ARE
           SUBJECT  TO  REDEMPTION   AT  $.001  PER  RIGHT  ON
           THE  TERMS  SET  FORTH  IN  THE  RIGHTS  AGREEMENT.
           RIGHTS OWNED BY AN ACQUIRING PERSON OR AN AFFILIATE
           OR AN ASSOCIATE  OF AN ACQUIRING PERSON (AS EACH IS
           DEFINED IN THE RIGHTS AGREEMENT) AND ANY SUBSEQUENT
           HOLDER OF SUCH RIGHTS MAY BECOME NULL AND VOID.


                                Right Certificate

                           HUMAN GENOME SCIENCES, INC.


     This certifies that , or registered assigns, is the registered owner of the
number of Rights set forth  above,  each of which  entitles  the owner  thereof,
subject to the terms, provisions and conditions of the Rights Agreement dated as
of May 20, 1998 (the "Rights Agreement") between HUMAN GENOME SCIENCES,  INC., a
Delaware  corporation  (the  "Company"),  and  American  Stock  Transfer & Trust
Company,  a New York  corporation  (the "Rights  Agent"),  to purchase  from the
Company at any time after the Distribution  Date (as such term is defined in the
Rights Agreement) and prior to 5:00 P.M. (New York City time) on May 20, 2008 at
the principal office of the Rights Agent in New York, New York, or at the office
of its successors as Rights Agent,  one fully paid,  nonassessable  share of the
Preferred  Stock,  par value  $0.01 per share,  of the Company  (the  "Preferred
Shares"),  at a purchase price of $250.00 per one  one-thousandth of a Preferred
Share (the  "Purchase  Price"),  upon  presentation  and surrender of this Right
Certificate  with the Form of Election to Purchase set forth on the reverse side
hereof and the Certificate contained therein duly executed. The number of Rights
evidenced by this Right  Certificate  (and the number of Preferred  Shares which
may be purchased upon exercise  thereof) set forth above, and the Purchase Price
set forth above, are the number and Purchase Price as of ________,  based on the
Preferred  Shares as constituted  at such date.  Upon the occurrence of an event
described in Section 11(a)(ii) of the Rights Agreement,  all Rights evidenced by
this Rights  Certificate which are beneficially owned by (i) an Acquiring Person
or an Affiliate  or Associate of an Acquiring  Person (as such terms are defined
in the  Rights  Agreement),  (ii) a  transferee  of any such  Acquiring  Person,
Associate or Affiliate,  or (iii) under certain  circumstances  specified in the
Rights Agreement,  a transferee of a person who, concurrently with or after such
transfer,  became an  Acquiring  Person,  shall become null and void and no such
holder  hereof  shall have any right with  respect to such Rights from and after
the occurrence of such event.

     As provided in the Rights  Agreement,  the Purchase Price and the number of
Preferred Shares or other securities which may be purchased upon the exercise of
the Rights  evidenced by this Right  Certificate are subject to modification and
adjustment upon the happening of certain events.

                                      B-1
<PAGE>

     This Right  Certificate  is subject  to all of the  terms,  provisions  and
conditions of the Rights Agreement,  which terms,  provisions and conditions are
hereby  incorporated  herein by  reference  and made a part  hereof and to which
Rights Agreement  reference is hereby made for a full description of the rights,
limitations  of rights,  obligations,  duties and  immunities  hereunder  of the
Rights Agent, the Company and the holders of the Right  Certificates.  Copies of
the  Rights  Agreement  are on file at the  principal  executive  offices of the
Company and the principal office of the Rights Agent in New York, New York.

     This Right  Certificate,  with or without  other Right  Certificates,  upon
surrender at the  principal  office of the Rights  Agent,  may be exchanged  for
another  Right  Certificate  or  Right  Certificates  of  like  tenor  and  date
evidencing  Rights  entitling the holder to purchase a like aggregate  number of
Preferred  Shares as the  Rights  evidenced  by the Right  Certificate  or Right
Certificates  surrendered  shall have  entitled the holder to purchase.  If this
Right  Certificate  shall be exercised in part,  the holder shall be entitled to
receive upon surrender  hereof another Right  Certificate or Right  Certificates
for the number of whole Rights not exercised.
    
     Subject to the provisions of the Rights Agreement,  the Rights evidenced by
this  Certificate may, but are not required to be (i) redeemed by the Company at
a redemption  price of $.001 per Right or (ii) exchanged in whole or in part for
Common Shares.

     No  fractional  Preferred  Shares will be issued  upon the  exercise of any
Right or  Rights  evidenced  hereby  (other  than  fractional  shares  which are
integral multiples of one one-thousandth of a Preferred Share, which may, at the
election of the  Company,  be  evidenced by  depositary  receipts),  but in lieu
thereof a cash payment will be made, as provided in the Rights Agreement.

     No holder of this Right  Certificate  shall be  entitled to vote or receive
dividends or be deemed for any purpose the holder of the Preferred  Shares or of
any other  securities  of the  Company  which may at any time be issuable on the
exercise hereof,  nor shall anything contained in the Rights Agreement or herein
be construed to confer upon the holder  hereof,  as such, any of the rights of a
stockholder of the Company or any right to vote for the election of directors or
upon any matter submitted to stockholders at any meeting thereof,  or to give or
withhold consent to any corporate  action,  or, to receive notice of meetings or
other  actions  affecting   stockholders  (except  as  provided  in  the  Rights
Agreement), or to receive dividends or subscription rights, or otherwise,  until
the  Right or  Rights  evidenced  by this  Right  Certificate  shall  have  been
exercised as provided in the Rights Agreement.

     This Right  Certificate  shall not be valid or  obligatory  for any purpose
until it shall have been countersigned by the Rights Agent.


                                      B-2

<PAGE>

     WITNESS the facsimile  signature of the proper  officers of the Company and
its corporate seal. Dated as of __________________, 1998.


ATTEST:                                    HUMAN GENOME SCIENCES, INC.


_________________________________          By _______________________________  
Secretary                                  Title:

Countersigned the _____ day of
____________, 19__:


AMERICAN STOCK TRANSFER &
  TRUST COMPANY


By ______________________________                                               
         Authorized Signature

















                                      B-3
<PAGE>

                   [Form of Reverse Side of Right Certificate]

                               FORM OF ASSIGNMENT

                (To be executed by the registered holder is such
               holder desires to transfer the Right Certificates.)


     FOR VALUE RECEIVED _______________________________________________________
hereby sells, assigns and transfers unto_______________________________________
_______________________________________________________________________________
_______________________________________________________________________________
this  Right  Certificate, together with all  right, title and  interest therein,
and does  hereby  irrevocably constitute and appoint  _________________________
Attorney,  to  transfer  the  within  Right  Certificate  on  the  books of the
within-named Company, with full power of substitution.


Dated:__________________, 19__


                                            ___________________________________
                                                         Signature


Signature Guaranteed:

     Signatures must be guaranteed by an eligible guarantor institution (a bank,
stockbroker,  savings and loan association or credit union with membership in an
approved signature  guarantee medallion program) pursuant to Rule 17Ad-15 of the
Securities Exchange Act of 1934.

- -------------------------------------------------------------------------------










                                      B-4

<PAGE>

            [Form of Reverse Side of Right Certificate -- continued]

                           CERTIFICATION FOR TRANSFER

                     (To be executed in connection with any
                       transfer of the Right Certificate.)

     The undersigned hereby certifies by checking the appropriate boxes that:

     (1) this  Right  Certificate  [ ] is [ ] is not being  sold,  assigned  and
transferred by or on behalf of a Person who is or was an Acquiring  Person or an
Affiliate or Associate of any such  Acquiring  Person (as such terms are defined
pursuant to the Rights Agreement);

     (2) after due inquiry and to the best knowledge of the undersigned,  it [ ]
did [ ] did not acquire the Rights evidenced by this Right  Certificate from any
Person who is, was or subsequently became an Acquiring Person or an Affiliate or
Associate of an Acquiring Person.



Dated:  ______________________, 19__           _______________________________
                                                           Signature



- -------------------------------------------------------------------------------





















                                      B-5
<PAGE>

            [Form of Reverse Side of Right Certificate -- continued]

                          FORM OF ELECTION TO PURCHASE

                      (To be executed if holder desires to
                        exercise the Right Certificate.)


To:      HUMAN GENOME SCIENCES, INC.

     The undersigned  hereby  irrevocably  elects to exercise  _________________
Rights  represented by this Right  Certificate to purchase the Preferred  Shares
issuable  upon the exercise of such Rights and requests  that  certificates  for
such Preferred Shares be issued in the name of:

Please insert social security
or other identifying number


_______________________________________________________________________________
                         (Please print name and address)
_______________________________________________________________________________
                         

If such  number of Rights  shall not be all the Rights  evidenced  by this Right
Certificate,  a new Right  Certificate for the balance  remaining of such Rights
shall be registered in the name of and delivered to:

Please insert social security
or other identifying number

_______________________________________________________________________________
                         (Please print name and address)

                                                                                

Dated ___________________, 19__

                                       ________________________________________
                                       Signature

                                       (Signature  must conform in all  respects
                                       to name of holder  as  specified  on  the
                                       face   of   this   Right  Certificate  in
                                       every  particular,   without   alteration
                                       or enlargement or  any change whatsoever)




                                      B-6


<PAGE>

            [Form of Reverse Side of Right Certificate -- continued]


Signature Guaranteed

     Signatures  must be  guaranteed  by a member firm of a registered  national
securities exchange, a member of the National Association of Securities Dealers,
Inc., or a commercial bank or trust company having an office or correspondent in
the United States.

- --------------------------------------------------------------------------------
                     CERTIFICATION FOR ELECTION TO PURCHASE

     The undersigned hereby certifies by checking the appropriate boxes that:

     (1) the  Rights  evidenced  by this Right  Certificate  [ ] are [ ] are not
being exercised by or on behalf of a Person who is or was an Acquiring Person or
an  Affiliate  or  Associate  of any such  Acquiring  Person  (as such terms are
defined pursuant to the Rights Agreement);

     (2) after due inquiry and to the best knowledge of the undersigned,  it [ ]
did [ ] did not acquire the Rights evidenced by this Right  Certificate from any
Person who is, was or subsequently became an Acquiring Person or an Affiliate or
Associate of an Acquiring Person.



Dated:  ______________________, 19__         __________________________________
                                                           Signature

- -------------------------------------------------------------------------------
                                     NOTICE

     The  signatures  in the  foregoing  Forms of  Assignment  and  Election  to
Purchase  must  correspond  to the name as  written  upon the face of this Right
Certificate in every particular, without alteration or enlargement or any change
whatsoever.

     In the event the  certification  set forth above in the Forms of Assignment
and Election to Purchase is not completed,  the Company will deem the beneficial
owner of the Rights  evidenced  by this  Right  Certificate  to be an  Acquiring
Person or an Affiliate or Associate thereof (as defined in the Rights Agreement)
and,  in the case of an  Assignment,  will affix a legend to that  effect on any
Right Certificates issued in exchange for this Rights Certificate.




                                      B-7

<PAGE>
                                                                      EXHIBIT C
                                                                                

                           HUMAN GENOME SCIENCES, INC.

                          SUMMARY OF RIGHTS TO PURCHASE
                                PREFERRED SHARES


     On May 20, 1998 the Board of Directors of Human Genome Sciences,  Inc. (the
"Company") declared a dividend of one preferred share purchase right (a "Right")
for each  outstanding  share of  common  stock,  par value  $.01 per share  (the
"Preferred  Shares"),  of the Company. The dividend was payable on June 26, 1998
to the  stockholders  of  record  on May  27,  1998.  Each  Right  entitles  the
registered holder to purchase from the Company one one-thousandth of a Preferred
Share at a price of  $250.00  per  share  (the  "Purchase  Price"),  subject  to
adjustment.  The  description  and terms of the Rights are set forth in a Rights
Agreement  (the  "Rights  Agreement")  between the Company  and  American  Stock
Transfer & Trust Company, as Rights Agent (the "Rights Agent"),  dated as of May
20, 1998.

     Until the earlier to occur of (i) 10 days  following a public  announcement
that a person  or group of  affiliated  or  associated  persons  (an  "Acquiring
Person") acquired, or obtained the right to acquire, beneficial ownership of 15%
or more of the  outstanding  Common  Shares  (more  than 20% of the  outstanding
Common  Shares  in the  case of the Bass  Investors)  or (ii) 10  Business  days
following  the  commencement  or  announcement  of an intention to make a tender
offer or exchange  offer the  consummation  of which  would  result in a Person,
together with its Affiliates and  Associates,  becoming the beneficial  owner of
15%  (more  than 20% of the  outstanding  Common  Shares in the case of a tender
offer or exchange offer commenced or announced by the Bass Investors) or more of
such  outstanding  Common  Shares (the  earlier of such dates  being  called the
"Distribution  Date"), the Rights will be evidenced,  with respect to any of the
Common Share  certificates  outstanding  as of the Record  Date,  by such Common
Share certificate with a copy of this Summary of Rights attached thereto.

     The Rights Agreement provides that, until the Distribution Date (or earlier
redemption or exercise of the Rights),  the Rights will be transferred  with and
only with the Common Shares.  Until the Distribution Date (or earlier redemption
or expiration  of the Rights),  new Common Share  certificates  issued after the
Record Date upon  transfer or new  issuance of the Common  Shares will contain a
notation incorporating the Rights Agreement by reference. Until the Distribution
Date (or earlier  redemption  or  expiration  of the Rights),  the surrender for
transfer of any  certificates  for Common  Shares  outstanding  as of the Record
Date,  even  without  such  notation or a copy of this  Summary of Rights  being
attached  thereto,  will also  constitute the transfer of the Rights  associated
with the Common Shares  represented by such certificate.  As soon as practicable
following the Distribution  Date,  separate  certificates  evidencing the Rights
("Right  Certificates") will be mailed to holders of record of the Common Shares
as of the close of business on the  Distribution  Date and such  separate  Right
Certificates alone will evidence the Rights.

                                      C-1
<PAGE>

     The Rights are not exercisable until the Distribution Date. The Rights will
expire on the  tenth  (10th)  anniversary  of the  Effective  Date,  unless  the
expiration  date is extended or the Rights are earlier  redeemed or exchanged by
the Company, in each case as described below.

     In the event that any person,  alone or together  with its  affiliates  and
associates,  becomes an Acquiring Person,  proper provision will be made so that
each holder of a Right, other than Rights that were or are beneficially owned by
the Acquiring  Person (which will thereafter be null and void),  will thereafter
have the right to receive upon  exercise  that number of Common  Shares having a
market value of two times the exercise price of the Right.  Further in the event
that the  Company  were  acquired  in a merger  or  other  business  combination
transaction  or 50% or more of its  consolidated  assets or  earning  power were
sold,  proper  provision  will  be made so that  each  holder  of a Right  shall
thereafter  have the right to  receive,  upon the  exercise  thereof at the then
current  exercise  price of the Right,  that number of shares of common stock of
the acquiring  company which at the time of such transaction would have a market
value of two times the  exercise  price of the  Right.  However,  Rights are not
exercisable  following the occurrence of any of the events set forth above until
such time as the Rights are no longer redeemable by the Corporation.

     No  fractional  Preferred  Shares will be issued  (other  than  fractional)
shares which are integral  multiples of one one-thousandth of a Preferred Share,
which may, at the election of the Company, be evidenced by depository  receipts)
and in lieu thereof, a payment in cash will be made based on the market price of
the Preferred Shares on the last trading date prior to the date of exercise.

     The Purchase  Price  payable,  and the number of Preferred  Shares or other
securities  or  property  issuable,  upon  exercise of the Rights are subject to
adjustment  from time to time to  prevent  dilution  (i) in the event of a stock
dividend on, or a subdivision, combination or reclassification of, the Preferred
Shares, (ii) upon the grant to holders of the Preferred Shares of certain rights
or  warrants  to  subscribe  for or  purchase  Preferred  Shares at a price,  or
securities  convertible into Preferred Shares with a conversion price, less than
the  then-current  market  price  of the  Preferred  Shares  or  (iii)  upon the
distribution to holders of the Preferred  Shares of evidences of indebtedness or
assets  (excluding  regular  periodic  cash  dividends  paid out of  earnings or
retained  earnings or dividends  payable in Preferred Shares) or of subscription
rights or warrants (other than those referred to above).

     At any time after any  person  becomes an  Acquiring  Person,  the Board of
Directors  of the Company  may, at its option,  exchange all or part of the then
outstanding and exercisable Rights (excluding Rights of an Acquiring Person that
have become void) for Common Shares at an exchange ratio of one Common Share per
Right,  appropriately  adjusted to reflect any stock  split,  stock  dividend or
similar  transaction  occurring  after  the  date  hereof.  Notwithstanding  the
foregoing, the Board of Directors shall not be empowered to effect such exchange
at any time  after  any  Acquiring  Person,  together  with all  Affiliates  and
Associates of such Person,  becomes the Beneficial Owner of more than 50% of the
Common Shares then outstanding.

                                      C-2
<PAGE>

     At any time prior to the earlier of the Share  Acquisition Date or the date
the Rights  expire,  the Rights are  redeemable at the election of a majority of
the board of directors of the Company,  in whole, but not in part, at a price of
$.001 per Right.

     Until a Right is  exercised,  the  holder  thereof,  as such,  will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive  dividends.  While the distribution of the Rights will not
be taxable to stockholders or to the Company,  stockholders may,  depending upon
the circumstances,  recognize taxable income in the event that the Rights become
exercisable  for Common  Stock (or other  consideration)  of the  Company or for
common stock of the acquiring company as set forth above.

     Other than those provisions relating to the principal economic terms of the
Rights,  any of the  provisions  of the Rights  Agreement  may be amended by the
Board of Directors of the Company  prior to the  Distribution  Date,  including,
without limitation, any amendment deemed to be necessary or appropriate in light
of any judicial or other legal developments, whether or not binding precedent in
respect of the Rights Agreement.  After the Distribution Date, the provisions of
the Rights Agreement may be amended by the Board in order to cure any ambiguity,
to make changes which do not adversely  affect the interest of holders of Rights
(excluding the interests of any Acquiring Person), or to shorten or lengthen any
time period under the Rights Agreement;  provided, however, that no amendment to
lengthen the time period governing  redemption shall be made at such time as the
Rights  are  not  redeemable  or any  other  time  unless  for  the  purpose  of
protecting,  enhancing  or  clarifying  the rights of the holders of the Rights.
Without limiting any of the foregoing,  the Board may amend the Rights Agreement
to lower the threshold for  exercisability  of the Rights (and the determination
of the  existence of an  Acquiring  Person) from 15% (or 20%, in the case of the
Bass  Investors) to any  percentage  greater than the greater of (i) the largest
percentage  of  outstanding  Common  Shares  then  known  to the  Company  to be
beneficially  owned by any Person or group or affiliated  or associated  persons
(other  than  the  Company,  employee  benefit  plans  of the  Company  and  its
subsidiaries  and, except in the case of a lowering of the 20%  threshhold,  the
Bass Investors) and (ii) 10%.

     A copy of the  Rights  Agreement  has been filed  with the  Securities  and
Exchange  Commission as and Exhibit to the Company's  Registration  Statement on
Form 8-A dated  _______ __,  1998.  A copy of the Rights  Agreement is available
free of charge from the Company. This summary description of the Rights does not
purport to be complete  and is  qualified  in its  entirety by  reference to the
Rights Agreement, as amended, which is hereby incorporated herein by reference.


Dated:  May 20, 1998


                                      C-3




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