As filed with the Securities and Exchange Commission on November 7, 1997
 Registration No.33-

                         SECURITIES AND EXCHANGE COMMISSION
                              Washington, D.C. 20549


                                     FORM S-8
                                REGISTRATION STATEMENT
                                        UNDER
                             THE SECURITIES ACT OF 1933


                                  Somatogen, Inc.
                  (Exact name of registrant as specified in its charter)

       Delaware                                          84-0991858
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                         2545 Central Avenue, Suite FD1
                          Boulder, Colorado 80301-2857
                                   (303) 440-9988
           (Address and telephone number of principal executive offices)

                  Amended and Restated Consultants Stock Option Plan
              Amended and Restated Nonemployee Director Stock Option Plan
                               (Full title of the plans)

                                  Timothy D. Hoogheem
                  Senior Vice President of Finance and Administration,
               Chief Financial Officer, Treasurer and Assistant Secretary
                                     SOMATOGEN, INC.
                             2545 Central Avenue, Suite FD1
                              Boulder, Colorado 80301-2857
                                     (303) 440-9988
              (Name, address, including zip code, and telephone number,
                        including area code, of agent for service)


                                      Copies to:

                                James C.T. Linfield, Esq.
                                    Cooley Godward LLP
                                2595 Canyon Blvd., Suite 250
                                   Boulder, Colorado 80302
                                       (303) 546-4000


                 Approximate date of commencement of proposed sale to
                       the public:  As soon as practicable after
                     this Registration Statement becomes effective.

                                                                  Page 1 of 7
                                                     Exhibit Index at Page: 7


<PAGE> 2

<TABLE>
<CAPTION>

                               CALCULATION OF REGISTRATION FEE

<S>                        <C>                <C>                      <C>                       <C>

 ========================  =================  ======================== ========================= =======================
                                                 Proposed Maximum          Proposed Maximum
  Title of Securities to     Amount to be       Offering Price Per        Aggregate Offering           Amount of
      be Registered         Registered (1)           Share (2)                 Price (2)             Registration Fee
 ========================= =================  ======================== ========================= =======================
 Stock Options and
 Common Stock (par value         300,000               $6.5625                 $1,968,750                 $596.53
 $.001)
 ========================= ================= ========================= ========================= =======================

</TABLE>

(1)      Comprised of 200,000 and 100,000 shares of Common Stock to be 
         registered under the Amended and Restated Nonemployee Director
         Stock Option Plan and the Amended and Restated Consultants Stock 
         Option Plan, respectively.

(2)      Estimated  solely  for the  purpose  of  calculating  the amount of the
         registration  fee. The offering price per share and aggregate  offering
         price  are based  upon the  closing  price as  reported  on the  Nasdaq
         National   Market,   pursuant  to  Rule  457(h)  of  the  Act,  of  the
         Registrant's  Common Stock on November 3, 1997,  for shares  subject to
         options  to be  granted  under the  Amended  and  Restated  Nonemployee
         Director  Stock  Option Plan and the Amended and  Restated  Consultants
         Stock Option Plan.

                     INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         The  following   documents   filed  by  Somatogen,   Inc.,  a  Delaware
corporation (the "Company" or the "Registrant") with the Securities and Exchange
Commission  (the   "Commission")   are   incorporated  by  reference  into  this
Registration Statement:

         (a) The Company's  Annual Report on Form 10-K for the fiscal year ended
June 30, 1997;

         (b) The  Registrant's  Quarterly  Report on Form  10-Q for the  quarter
ended September 30, 1997;

         (c) A description of the Company's Common Stock,  which is contained in
the Form 8-A  Registration  Statement  filed by the Company with the  Commission
which was  declared  effective  on August 1, 1991,  as amended  through the date
hereof; and

<PAGE> 3

         (d) All reports and other documents  subsequently  filed by the Company
pursuant to Sections 13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act
of 1934, as amended (the "Exchange Act") prior to the filing of a post-effective
amendment  which  indicates that all securities  offered have been sold or which
deregisters  all  securities  then  remaining  unsold,  shall  be  deemed  to be
incorporated by reference herein and to be a part of this registration statement
from the date of the filing of such reports and documents.


                          DESCRIPTION OF SECURITIES

         Not applicable.


                   INTERESTS OF NAMED EXPERTS AND COUNSEL

         The validity of the issuance of the Common  Stock  offered  pursuant to
the Amended and Restated  Nonemployee Director Stock Option Plan and the Amended
and Restated  consultants  Stock Option Plan will be passed upon for the Company
by Cooley Godward LLP. As of the date hereof,  certain members of Cooley Godward
LLP beneficially owned 19,794 shares of Common Stock.


                 INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Under Section 145 of the Delaware General  Corporation Law, the Company
has broad powers to indemnify  its directors  and officers  against  liabilities
they may incur in such  capacities,  including  liabilities  under the Act.  The
Company's  Bylaws  require the Company to indemnify  its directors and executive
officers, and permit the Company to indemnify its employees and other agents, to
the extent  permitted by Delaware law. Under the company's  Bylaws,  indemnified
parties are entitled to  indemnification  for negligence,  gross  negligence and
otherwise  to the fullest  extent  permitted by law. The Bylaws also require the
Company to advance  litigation  expenses in the case of  stockholder  derivative
actions or other actions,  against an undertaking  by the  indemnified  party to
repay such advances if it is ultimately determined that the indemnified party is
not entitled to indemnification.

         The Company  has entered  into  indemnity  agreements  with each of its
directors and executive  officers.  Such indemnity agreements contain provisions
which are in some respects broader than the specific indemnification  provisions
contained in Delaware law.


                                  EXHIBITS

Exhibit
Number

    3.4*    Bylaws.
    4.1*    Certificate  of  Incorporation, as amended.   
    4.5*    Specimen  stock certificate. 
    5.1     Opinion of Cooley Godward LLP.
   23.1     Consent of Price Waterhouse LLP, Independent Accountants.
   23.3     Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
   24.1     Power of Attorney.  Reference is made to the signature page.
   10.78    Registrant's Amended and Restated Nonemployee Director Stock Option
            Plan.
   10.79    Registrant's Amended and Restated Consultants Stock Option Plan.

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

*        Filed  as an  exhibit  to the  Form  S-1  Registration  Statement  (No.
         33-41229),  as amended through the date hereof, and incorporated herein
         by reference.



<PAGE> 4



                                  UNDERTAKINGS

I.       The undersigned registrant hereby undertakes:

         A. To file,  during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

             1. To include any prospectus required by section 10(a)(3) of the
Securities Act;

             2. To reflect in the  prospectus  any facts or events arising after
the  effective  date  of  the   registration   statement  (or  the  most  recent
post-effective  amendment  thereof)  which,  individually  or in the  aggregate,
represent a fundamental  change in the information set forth in the registration
statement.  Notwithstanding the foregoing, any increase or decrease in volume of
securities  offered (if the total dollar value of  securities  offered would not
exceed that which was  registered) and any deviation from the low or high end of
the estimated  maximum offering range may be reflected in the form of prospectus
filed with the  Commission  pursuant  to Rule  424(b)  (ss.  230.424(b)  of this
chapter) if, in the aggregate, the changes in volume and price represent no more
than a 20%  change  in the  maximum  aggregate  offering  price set forth in the
"Calculation of Registration Fee" table in the effective registration statement.

             3. To include any material  information with respect to the plan of
distribution  not  previously  disclosed  in the  registration  statement or any
material change to such information in the registration statement.

         B.  That,  for the  purpose  of  determining  any  liability  under the
Securities Act, each such  post-effective  amendment shall be deemed to be a new
registration  statement  relating  to the  securities  offered  herein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

         C. To remove from  registration by means of a post-effective  amendment
any of the securities being registered which remain unsold at the termination of
the offering.

II.      The  undersigned   registrant  hereby  undertakes  that,  for  purposes
of  determining  any  liability  under the  Securities  Act,  each filing of the
registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the Registration  Statement shall be deemed to be a
new registration  statement  relating to the securities  offered herein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

III.     Insofar as indemnification for liabilities arising under the Securities
Act may be  permitted to  directors,  officers  and  controlling  persons of the
registrant pursuant to the foregoing  provisions,  or otherwise,  the registrant
has been advised that in the opinion of the Securities  and Exchange  Commission
such indemnification is against public policy as expressed in the Securities Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred or paid by a director,  officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as  expressed  in the  Securities  Act and will be  governed by the final
adjudication of such issue.


<PAGE> 5



                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in Boulder,  State of  Colorado,  on the 7th day of November,
1997.

                                         SOMATOGEN, INC.

                                         By: Timothy D. Hoogheem
                                             Senior Vice President of Finance
                                             and Administration, Chief Financial
                                             Officer, Treasurer and Assistant
                                             Secretary


                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE  PRESENTS,  that each person whose  signature
appears  below  constitutes  and appoints  each of Andre de Bruin and Timothy D.
Hoogheem, his/her true and lawful attorney-in-fact and agent, with full power of
substitution  and  resubstitution,  for him/her and in his/her  name,  place and
stead,  in any and all  capacities,  to sign any and all  amendments  (including
post-effective amendments) to this Registration Statement, and to file the same,
with all exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange  Commission,  granting unto said  attorneys-in-fact  and
agents,  and each of them,  full power and  authority to do and perform each and
every act and thing requisite and necessary to be done in connection  therewith,
as fully to all intents and  purposes as he might or could do in person,  hereby
ratifying and confirming all that said  attorneys-in-fact  and agents, or any of
them, or their or his substitutes or substitute,  may lawfully do or cause to be
done by virtue hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the dates indicated.

<TABLE>
<CAPTION>

Signature              Title                                  Date
---------              -----                                  ----
<S>                    <C>                                    <C>

Andre de Bruin         Chairman of the Board, President,      November 7, 1997
-------------------    Chief Executive Officer
                       (Principal executive officer)

Timothy D. Hoogheem    Senior Vice President of Finance and   November 7, 1997
-------------------    and Administration, Chief Financial
                       Officer, Treasurer and Assistant
                       Secretary (Principal financial officer)

Conrad A. McCarty      Corporate Controller                   November 7, 1997
-------------------    (Principal accounting officer)

</TABLE>

<PAGE> 6

<TABLE>
<CAPTION>

Signature                         Title                      Date
---------                         -----                      ----
<S>                               <C>                        <C>

Carlos A. Ferrer                  Director                   November 7, 1997
---------------------------


Bernadine Healy, M.D.             Director                   November 7, 1997
---------------------------


Gene I. Miller                    Director                   November 7, 1997
---------------------------


George B. Rathmann, Ph.D.         Director                   November 7, 1997
---------------------------


Jack W. Schuler                   Director                   November 7, 1997
---------------------------


Ralph Snyderman, M.D.             Director                   November 7, 1997
---------------------------


</TABLE>


<PAGE> 7



                               INDEX TO EXHIBITS


Exhibit
Number

  3.4*     Bylaws.
  4.1*     Certificate of Incorporation, as amended.
  4.5*     Specimen stock certificate.
  5.1      Opinion of Cooley Godward LLP.
 23.1      Consent of Price Waterhouse LLP, Independent Accountants.
 23.3      Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
 24.1      Power of Attorney.  Reference is made to the signature page.
 10.78     Registrant's Amended and Restated Nonemployee Director Stock Option
           Plan.
 10.79     Registrant's Amended and Restated Consultants Stock Option Plan.

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

*  Filed  as an  exhibit  to the  Form  S-1  Registration  Statement  (No.
   33-41229),  as amended through the date hereof, and incorporated herein
   by reference.
[{"type": "S-8", "sequence": "1", "secsgml_size_bytes": 16875}]
{"company-data": {"conformed-name": "SOMATOGEN INC", "cik": "0000818594", "assigned-sic": "2836", "irs-number": "840991858", "state-of-incorporation": "DE", "fiscal-year-end": "0630"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-39783", "film-number": "97710494"}, "business-address": {"street1": "2545 CENTRAL AVE", "street2": "SUITE FDI", "city": "BOULDER", "state": "CO", "zip": "80301", "phone": "3034409988"}}
As filed with the Securities and Exchange Commission on November 7, 1997
 Registration No.33-

                         SECURITIES AND EXCHANGE COMMISSION
                              Washington, D.C. 20549

                                     FORM S-8
                                REGISTRATION STATEMENT
                                        UNDER
                             THE SECURITIES ACT OF 1933

                                  Somatogen, Inc.
                  (Exact name of registrant as specified in its charter)

       Delaware                                          84-0991858
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                         2545 Central Avenue, Suite FD1
                          Boulder, Colorado 80301-2857
                                   (303) 440-9988
           (Address and telephone number of principal executive offices)

                  Amended and Restated Consultants Stock Option Plan
              Amended and Restated Nonemployee Director Stock Option Plan
                               (Full title of the plans)

                                  Timothy D. Hoogheem
                  Senior Vice President of Finance and Administration,
               Chief Financial Officer, Treasurer and Assistant Secretary
                                     SOMATOGEN, INC.
                             2545 Central Avenue, Suite FD1
                              Boulder, Colorado 80301-2857
                                     (303) 440-9988
              (Name, address, including zip code, and telephone number,
                        including area code, of agent for service)

                                      Copies to:

                                James C.T. Linfield, Esq.
                                    Cooley Godward LLP
                                2595 Canyon Blvd., Suite 250
                                   Boulder, Colorado 80302
                                       (303) 546-4000

                 Approximate date of commencement of proposed sale to
                       the public:  As soon as practicable after
                     this Registration Statement becomes effective.

                                                                  Page 1 of 7
                                                     Exhibit Index at Page: 7
2
CALCULATION OF REGISTRATION FEE
========================  =================  ======================== ========================= =======================
                                                 Proposed Maximum          Proposed Maximum
  Title of Securities to     Amount to be       Offering Price Per        Aggregate Offering           Amount of
      be Registered         Registered (1)           Share (2)                 Price (2)             Registration Fee
 ========================= =================  ======================== ========================= =======================
 Stock Options and
 Common Stock (par value         300,000               $6.5625                 $1,968,750                 $596.53
 $.001)
 ========================= ================= ========================= ========================= =======================
(1)      Comprised of 200,000 and 100,000 shares of Common Stock to be 
         registered under the Amended and Restated Nonemployee Director
         Stock Option Plan and the Amended and Restated Consultants Stock 
         Option Plan, respectively.

(2)      Estimated  solely  for the  purpose  of  calculating  the amount of the
         registration  fee. The offering price per share and aggregate  offering
         price  are based  upon the  closing  price as  reported  on the  Nasdaq
         National   Market,   pursuant  to  Rule  457(h)  of  the  Act,  of  the
         Registrant's  Common Stock on November 3, 1997,  for shares  subject to
         options  to be  granted  under the  Amended  and  Restated  Nonemployee
         Director  Stock  Option Plan and the Amended and  Restated  Consultants
         Stock Option Plan.

                     INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

         The  following   documents   filed  by  Somatogen,   Inc.,  a  Delaware
corporation (the "Company" or the "Registrant") with the Securities and Exchange
Commission  (the   "Commission")   are   incorporated  by  reference  into  this
Registration Statement:

         (a) The Company's  Annual Report on Form 10-K for the fiscal year ended
June 30, 1997;

         (b) The  Registrant's  Quarterly  Report on Form  10-Q for the  quarter
ended September 30, 1997;

         (c) A description of the Company's Common Stock,  which is contained in
the Form 8-A  Registration  Statement  filed by the Company with the  Commission
which was  declared  effective  on August 1, 1991,  as amended  through the date
hereof; and
3

         (d) All reports and other documents  subsequently  filed by the Company
pursuant to Sections 13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act
of 1934, as amended (the "Exchange Act") prior to the filing of a post-effective
amendment  which  indicates that all securities  offered have been sold or which
deregisters  all  securities  then  remaining  unsold,  shall  be  deemed  to be
incorporated by reference herein and to be a part of this registration statement
from the date of the filing of such reports and documents.

                          DESCRIPTION OF SECURITIES

         Not applicable.

                   INTERESTS OF NAMED EXPERTS AND COUNSEL

         The validity of the issuance of the Common  Stock  offered  pursuant to
the Amended and Restated  Nonemployee Director Stock Option Plan and the Amended
and Restated  consultants  Stock Option Plan will be passed upon for the Company
by Cooley Godward LLP. As of the date hereof,  certain members of Cooley Godward
LLP beneficially owned 19,794 shares of Common Stock.

                 INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Under Section 145 of the Delaware General  Corporation Law, the Company
has broad powers to indemnify  its directors  and officers  against  liabilities
they may incur in such  capacities,  including  liabilities  under the Act.  The
Company's  Bylaws  require the Company to indemnify  its directors and executive
officers, and permit the Company to indemnify its employees and other agents, to
the extent  permitted by Delaware law. Under the company's  Bylaws,  indemnified
parties are entitled to  indemnification  for negligence,  gross  negligence and
otherwise  to the fullest  extent  permitted by law. The Bylaws also require the
Company to advance  litigation  expenses in the case of  stockholder  derivative
actions or other actions,  against an undertaking  by the  indemnified  party to
repay such advances if it is ultimately determined that the indemnified party is
not entitled to indemnification.

         The Company  has entered  into  indemnity  agreements  with each of its
directors and executive  officers.  Such indemnity agreements contain provisions
which are in some respects broader than the specific indemnification  provisions
contained in Delaware law.

                                  EXHIBITS

Exhibit
Number

    3.4*    Bylaws.
    4.1*    Certificate  of  Incorporation, as amended.   
    4.5*    Specimen  stock certificate. 
    5.1     Opinion of Cooley Godward LLP.
   23.1     Consent of Price Waterhouse LLP, Independent Accountants.
   23.3     Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
   24.1     Power of Attorney.  Reference is made to the signature page.
   10.78    Registrant's Amended and Restated Nonemployee Director Stock Option
            Plan.
   10.79    Registrant's Amended and Restated Consultants Stock Option Plan.

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

*        Filed  as an  exhibit  to the  Form  S-1  Registration  Statement  (No.
         33-41229),  as amended through the date hereof, and incorporated herein
         by reference.
4

                                  UNDERTAKINGS

I.       The undersigned registrant hereby undertakes:

         A. To file,  during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

             1. To include any prospectus required by section 10(a)(3) of the
Securities Act;

             2. To reflect in the  prospectus  any facts or events arising after
the  effective  date  of  the   registration   statement  (or  the  most  recent
post-effective  amendment  thereof)  which,  individually  or in the  aggregate,
represent a fundamental  change in the information set forth in the registration
statement.  Notwithstanding the foregoing, any increase or decrease in volume of
securities  offered (if the total dollar value of  securities  offered would not
exceed that which was  registered) and any deviation from the low or high end of
the estimated  maximum offering range may be reflected in the form of prospectus
filed with the  Commission  pursuant  to Rule  424(b)  (ss.  230.424(b)  of this
chapter) if, in the aggregate, the changes in volume and price represent no more
than a 20%  change  in the  maximum  aggregate  offering  price set forth in the
"Calculation of Registration Fee" table in the effective registration statement.

             3. To include any material  information with respect to the plan of
distribution  not  previously  disclosed  in the  registration  statement or any
material change to such information in the registration statement.

         B.  That,  for the  purpose  of  determining  any  liability  under the
Securities Act, each such  post-effective  amendment shall be deemed to be a new
registration  statement  relating  to the  securities  offered  herein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

         C. To remove from  registration by means of a post-effective  amendment
any of the securities being registered which remain unsold at the termination of
the offering.

II.      The  undersigned   registrant  hereby  undertakes  that,  for  purposes
of  determining  any  liability  under the  Securities  Act,  each filing of the
registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the Registration  Statement shall be deemed to be a
new registration  statement  relating to the securities  offered herein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

III.     Insofar as indemnification for liabilities arising under the Securities
Act may be  permitted to  directors,  officers  and  controlling  persons of the
registrant pursuant to the foregoing  provisions,  or otherwise,  the registrant
has been advised that in the opinion of the Securities  and Exchange  Commission
such indemnification is against public policy as expressed in the Securities Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred or paid by a director,  officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as  expressed  in the  Securities  Act and will be  governed by the final
adjudication of such issue.
5

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in Boulder,  State of  Colorado,  on the 7th day of November,
1997.

                                         SOMATOGEN, INC.

                                         By: Timothy D. Hoogheem
                                             Senior Vice President of Finance
                                             and Administration, Chief Financial
                                             Officer, Treasurer and Assistant
                                             Secretary

                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE  PRESENTS,  that each person whose  signature
appears  below  constitutes  and appoints  each of Andre de Bruin and Timothy D.
Hoogheem, his/her true and lawful attorney-in-fact and agent, with full power of
substitution  and  resubstitution,  for him/her and in his/her  name,  place and
stead,  in any and all  capacities,  to sign any and all  amendments  (including
post-effective amendments) to this Registration Statement, and to file the same,
with all exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange  Commission,  granting unto said  attorneys-in-fact  and
agents,  and each of them,  full power and  authority to do and perform each and
every act and thing requisite and necessary to be done in connection  therewith,
as fully to all intents and  purposes as he might or could do in person,  hereby
ratifying and confirming all that said  attorneys-in-fact  and agents, or any of
them, or their or his substitutes or substitute,  may lawfully do or cause to be
done by virtue hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the dates indicated.
Signature              Title                                  Date
---------              -----                                  ----
Andre de Bruin         Chairman of the Board, President,      November 7, 1997
-------------------    Chief Executive Officer
                       (Principal executive officer)

Timothy D. Hoogheem    Senior Vice President of Finance and   November 7, 1997
-------------------    and Administration, Chief Financial
                       Officer, Treasurer and Assistant
                       Secretary (Principal financial officer)

Conrad A. McCarty      Corporate Controller                   November 7, 1997
-------------------    (Principal accounting officer)
6
Signature                         Title                      Date
---------                         -----                      ----
Carlos A. Ferrer                  Director                   November 7, 1997
---------------------------

Bernadine Healy, M.D.             Director                   November 7, 1997
---------------------------

Gene I. Miller                    Director                   November 7, 1997
---------------------------

George B. Rathmann, Ph.D.         Director                   November 7, 1997
---------------------------

Jack W. Schuler                   Director                   November 7, 1997
---------------------------

Ralph Snyderman, M.D.             Director                   November 7, 1997
---------------------------
7

                               INDEX TO EXHIBITS

Exhibit
Number

  3.4*     Bylaws.
  4.1*     Certificate of Incorporation, as amended.
  4.5*     Specimen stock certificate.
  5.1      Opinion of Cooley Godward LLP.
 23.1      Consent of Price Waterhouse LLP, Independent Accountants.
 23.3      Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.
 24.1      Power of Attorney.  Reference is made to the signature page.
 10.78     Registrant's Amended and Restated Nonemployee Director Stock Option
           Plan.
 10.79     Registrant's Amended and Restated Consultants Stock Option Plan.

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*  Filed  as an  exhibit  to the  Form  S-1  Registration  Statement  (No.
   33-41229),  as amended through the date hereof, and incorporated herein
   by reference.