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                                                                   EXHIBIT 10.24

                       PROTEIN POLYMER TECHNOLOGIES, INC.
                 1996 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN



1.     Purpose of the Plan.

       The purpose of the 1996 Non-Employee Directors' Stock Option Plan of the
Company is to provide incentives which will attract and retain highly competent
persons as directors of the Company by providing them with opportunities to
acquire a proprietary interest in the Company by the grant to such persons of
nonqualified Stock Options which may result in their ownership of Common Stock
of the Company.

2.     Definitions.

       (a) "Administrator" shall mean the Board or, if and to the extent the
Board delegates any of its authority hereunder in accordance with Section 4(b)
hereof, the Committee.

       (b) "Board" means the Board of Directors of the Company.

       (c) "Committee" means a committee appointed by the Board to administer
the Plan pursuant to Section 4(b) hereof.

       (d) "Common Stock" means the common stock, $.01 par value, of the
Company.

       (e) "Company" means Protein Polymer Technologies, Inc., a Delaware
corporation.

       (f) "Date of Grant" means the date determined as set forth in Section 6
hereof.

       (g) "Disability" means any medically determinable physical or mental
impairment of a Participant, as determined by the Administrator, in its complete
and sole discretion, which is expected to last for a period of at least 180 days
as a result of which such Participant is unable to engage in any substantial
gainful activity.  All determinations as to a Participant's disabled status, and
the date and extent of any disability, shall be made by the Administrator upon
the basis of such information as it deems necessary or desirable.

       (h) "Eligible Participant" means a Participating Director.

       (i) "Exchange Act" means the Securities Exchange Act of 1934, as amended.

       (j) "Fair Market Value" on a given date means (a) the mean between the
highest and the lowest reported sales prices for the Common Stock on that date
(or, if there were no such sales on that date, on the next most recent date on
which there were such sales) as reported on the New York Stock Exchange
Composite Tape; or (b) if the Common Stock is not then listed on a national
securities exchange, (i) the mean between the closing bid and asked price
quotations for the Common Stock on that date (or if none on that date, on the
next most recent date) as reported by the National Association of Securities
Dealers Automatic Quotation System or any successor thereto, or (ii) the closing
price of the Common Stock on NASDAQ if the Common Stock is designated as a
National Market Security.

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       (k) "Normal Board Retirement" means, in conjunction with termination of a
Participant's services as a member of the Board for any reason other than death
or Disability, the determination of the Administrator or the Nominating
Committee of the Board that such termination constitutes Normal Board
Retirement.  In the absence of such a determination, termination of a
Participant's services as a member of the Board shall be deemed to be for
reasons other than Normal Board Retirement.

       (l) "Option" or "Stock Option" means a stock option that does not qualify
as an incentive stock option within the meaning of Section 422 of the Internal
Revenue Code of 1986, as amended.

       (m) "Option Agreement" means an option agreement signed by the Company
and the Participant in such form and including such terms and conditions not
inconsistent with the Plan as the Administrator may in its discretion from time
to time determine.

       (n) "Participant" means any Eligible Participant who elects to receive
Options pursuant to Section 6 hereof.

       (o) "Participating Director" means a member of the Board who is not an
employee of the Company or any of its present or future parent or subsidiary
corporations.

       (p) "Plan" means the 1996 Non-Employee Directors' Stock Incentive Plan as
set forth herein, and as it may be amended from time to time.

3.     Shares of Common Stock Subject to the Plan.

       (a) Subject to the provisions of Section 3(c) and Section 8 of the Plan,
the aggregate number of shares of Common Stock that may be issued or transferred
or exercised pursuant to Options granted under the Plan will not exceed 250,000.

       (b) The shares to be delivered under the Plan will be made available from
authorized but unissued shares of Common Stock.

       (c) Shares of Common Stock subject to an unexercised portion of any Stock
Option granted under the Plan which expires or terminates or is cancelled will
again become available for the grant of further Options hereunder.

4.     Administration of the Plan.

       (a) The Plan shall, to the extent possible, be self-effectuating.  The
Plan will be administered by the Board.  The Board is authorized and empowered
to administer the Plan, which administration shall include (but is not limited
to) authority to (i) construe and interpret the plan and any agreements defining
the rights and obligations of the Company and Participants under the Plan; (ii)
prescribe, amend and rescind rules and regulations relating to the Plan; (iii)
further define the terms used in the Plan; (iv) determine the rights and
obligations of Participants under the Plan; and (v) make all other
determinations necessary or advisable for the administration of the Plan.  Each
Option granted under the Plan shall be evidenced by an Option Agreement.

       (b) The Board of Directors may, in its discretion, delegate any or all of
its authority under the Plan to a committee consisting of two or more directors
of the Company, so long as allowable under applicable law.

       (c) No member of the Board or the Committee will be liable for any action
or determination made in good faith by the Board or the Committee with respect
to the Plan or any Option under it, 

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including, without limitation, adjustments pursuant to Section 8. In making
determinations under the Plan, the Board or the Committee may obtain and may
rely upon the advice of independent counsel and accountants and other advisors
to the Company. No member of the Board or the Committee, nor an officer of the
Company shall be liable for any such action or determination taken or made in
good faith with respect to the Plan or any Option granted hereunder.

5.     Participation.

       Options shall be granted to each Participating Director exclusively in
accordance with the provisions set forth in Section 6 hereof.

6.     Annual Option Grants.

       (a) On June 1 (or if June 1 is not a business day, on the next succeeding
business day) in each calendar year, commencing in 1996, during the term of the
Plan, there shall be granted automatically (without any action by the
Administrator) a Stock Option (the Date of Grant which shall be such date in
June) to each Participating Director then in office to purchase 5,000 shares of
Common Stock (subject to adjustment pursuant to Section 8 hereof).

       (b) In any calendar year after 1996 in which a person shall become a
Participating Director for the first time, there shall be granted automatically
(without any action by the Administrator) a Stock Option (the Date of Grant of
which shall be the date such person shall have become a Participating Director)
to such person to purchase 5,000 shares of Common Stock (subject to adjustment
pursuant to Section 8 hereof).

       (c) Notwithstanding the provisions of paragraphs (a) and (b) above, no
Participating Director shall receive more than one Stock Option under this
Section 6 in any calendar year.

7.     Terms and Conditions of Stock Options.

       (a) Purchase Price.  The purchase price of Common Stock under each Stock
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Option granted under Section 6 will be equal to the Fair Market Value of the
Common Stock on the Date of Grant.

       (b) Exercise Period.  Stock Options may be exercised from time to time in
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accordance with the terms of the applicable Option Agreement and this Section 7.
No Stock Option granted pursuant to Section 6 hereof shall be exercised prior to
the six months after its Date of Grant.  Notwithstanding anything to the
contrary in the Plan or any Option Agreement hereunder, no Option granted
hereunder shall be exercised after ten years from its Date of Grant.

       (c) Payment of Purchase Price.  Upon the exercise of a Stock Option, the
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purchase price will be payable in full in cash or its equivalent acceptable to
the Company.  In the discretion of the Administrator, the purchase price may be
paid by the assignment and delivery to the Company of shares of Common Stock or
a combination of cash and such shares equal in value to the exercise price.  Any
shares so assigned and delivered to the Company in payment or partial payment of
the purchase price will be valued at their Fair Market Value on the exercise
date.

       (d) No Fractional Shares.  No fractional shares will be issued pursuant
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to the exercise of a Stock Option nor will any cash payment be made in lieu of
fractional shares.

       (e) Termination of Directorship.  If a Participant's services as a member
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of the Board terminate by reason of death, Disability or Normal Board
Retirement, an Option granted hereunder held by such Participant shall be
automatically accelerated with respect to its exercisability and shall become

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immediately exercisable in full for the remaining number of shares of Common
Stock subject to such Option for three years after the date of such termination
or until the expiration of the stated term of such Option, whichever period is
shorter, and thereafter such Option shall terminate; provided, however, that if
a Participant dies or suffers a Disability during said three year period after
Normal Board Retirement such Option shall remain exercisable in full for a
period of three years after the date of such death or Disability or until the
expiration of the stated term of such Option, whichever period is shorter, and
thereafter such Option shall terminate. If a Participant's services as a member
of the Board terminate for any other reason, any portion of an Option granted
hereunder held by such Participant which is not then exercisable shall terminate
and any portion of such Option which is then exercisable may be exercised for
three months after the date of such termination or until the expiration of the
stated term of such Option, whichever period is shorter, and thereafter such
Option shall terminate; provided, however, that if a Participant dies or suffers
a Disability during such three month period, such Option may be exercised for a
period of one year after the date of such Participant's death or Disability or
until the expiration of the stated term of such Option, whichever period is
shorter, in accordance with its terms, but only to the extent exercisable on the
date of the Participant's death or Disability.

8.     Adjustment Provisions.

       (a) Subject to Section 8(b), if the outstanding shares of Common Stock of
the Company are increased, decreased or exchanged for a different number or kind
of shares or other securities, or if additional shares or new or different
shares or other securities are distributed with respect to such shares of Common
Stock or other securities, through merger, consolidation, sale of all or
substantially all the property of the Company, reorganization, recapitalization,
reclassification, stock dividend, stock split, reverse stock split or other
distribution with respect to such shares of Common Stock or other securities, an
appropriate and proportionate adjustment shall be made in (i) the maximum number
and kind of shares or other securities provided in Section 3(a), (ii) the number
and kind of shares or other securities subject to the then-outstanding Stock
Options, (iii) the price for each share or other unit or any other securities
subject to then-outstanding Stock Options without change in the aggregate
purchase price or value as to which such Stock Options remain exercisable and
(iv) the number, kind and price of shares or other securities to be granted
pursuant to Section 6 hereof.

       (b) Notwithstanding the provisions of Section 8(a), upon dissolution or
liquidation of the Company or upon a reorganization, merger or consolidation of
the Company with one or more corpo rations as a result of which the Company is
not the surviving corporation or as a result of which the outstanding Common
Stock is converted into or exchanged for cash or securities of another issuer or
both, or upon the sale of all or substantially all the assets of the Company,
all restrictions applicable to the exercise of outstanding Stock Options shall
continue in full force and effect and provision shall be made in connection with
such transaction for the continuance of the Plan and the assumption of the
outstanding stock Options by or the substitution for such Options of new options
covering the stock of the successor corporation, or a parent or subsidiary
thereof or the Company, with appropriate and proportionate adjustment in (i) the
number and kind of shares or other securities or cash or other property subject
to such Options and (ii) the price for each share or other unit of any other
securities or cash or other property subject to such Options without change in
the aggregate purchase price or value as to which such Options remain
exercisable; provided, however, that if no public market exists for the Common
Stock or the other securities or property which would be subject to such Options
after consummation of such transaction, such Options shall be converted into the
right to receive, upon exercise thereof, an amount of cash equal to the amount
determined by the Administrator to be the fair market value of the effective
date of such transaction of the stock, other securities, cash and other property
that a share of Common Stock is entitled to receive, or into which it is
converted, pursuant to such transaction.

       (c) Adjustments under Sections 8(a) and 8(b) will be made by the
Administrator, whose determination as to what adjustments will be made and the
extent thereof will be final, binding, and 

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conclusive in the absence of manifest error or arbitrary action. No fractional
interest will be issued under the Plan on account of any such adjustments.

9.     General Provisions.

       (a) The grant of any Stock Option under the Plan may also be subject to
such other provisions (whether or not applicable to the Stock Option awarded to
any other Participant) as the Administrator determines appropriate including,
without limitation, provisions to assist the participant in financing the
purchase of Common Stock through the exercise of Stock Options, provisions for
the forfeiture of or restrictions on resale or other disposition of shares
acquired under any form of benefit, provisions giving the Company the right to
repurchase shares acquired under any form of benefit in the event the
Participant elects to dispose of such share, provisions to comply with federal
and state securities laws and federal and state income tax withholding
requirements and to such approvals by any regulatory or governmental agency
which may be necessary or advisable in connection therewith.

       In connection with the administration of the Plan or the grant of any
Stock Option, the Administrator may impose such further limitations or
conditions as in its opinion may be required or advisable to satisfy, or secure
the benefits of, applicable regulatory requirements (including those rules
promulgated under Section 16 of the Exchange Act or those rules that facilitate
exemption from or compliance with the Act of the Exchange Act), the requirements
of any stock exchange or NASDAQ upon which such shares or shares of the same
class are then listed, and any blue sky or other securities laws applicable to
such shares.

       (b) No person shall be entitled to the privileges of stock ownership in
respect of shares of stock which are subject to Options hereunder until such
person shall have become the holder of record of such shares.

       (c) Options shall not be transferable by the Participants other than by
will or the laws of descent and distribution, and during the lifetime of any
Participant shall be exercisable only by such Participant, except that to the
extent permitted by applicable law, and Rule 16b-3 promulgated under the
Exchange Act, the Administrator may permit a Participant to designate in writing
during his lifetime a beneficiary to receive and exercise Stock Options in the
event of such Participant's death.  Following the death of a Participant, Stock
Options held by such Participant shall be exercisable, in accordance with their
terms, by such designated beneficiary or, if no such beneficiary has been
designated, by the Participant's estate or by the person or persons who acquire
the right to exercise it by bequest or inheritance.  Any attempt to transfer,
assign, pledge, hypothecate or otherwise dispose of, or to subject to execution,
attachment or similar process, any Stock Option granted hereunder, contrary to
the provisions hereof, shall be void and ineffective, shall give no rights to
the purported transferee, and shall at the sole discretion of the Administrator
result in forfeiture of such Stock Option with respect to the shares involved in
such attempt.

       (d) The Plan and all Stock Options granted under the Plan and the
documents evidencing Stock Options shall be governed by, and construed in
accordance with, the laws of the state of California.

10.    Amendment and Termination.

       (a) The Board will have the power, in its discretion, to amend, suspend
or terminate the Plan at any time.  No such amendment will, without approval of
the stockholders of the Company, except as provided in Section 8 of the Plan:

           (i)   Change the class of persons eligible to receive Stock Options
       under the Plan; or

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           (ii)  Increase the number of shares of Common Stock subject to the
       Plan.

       (b) No amendment, suspension or termination of the Plan will, without the
consent of the Participant, alter, terminate, impair or adversely affect any
right or obligation under any Stock Option previously granted under the Plan.

       (c) The Plan shall not be amended more than once every six months, other
than to comport with changes in the Internal Revenue Code, the Employee
Retirement Income Security Act, or the rules thereunder.

11.    Effective Date of Plan and Duration of Plan.

       This Plan will become effective upon adoption by the Board subject to
approval by the holders of a majority of the outstanding shares of Common Stock
present in person or by proxy and entitled to vote at a meeting of stockholders
of the Company held any time after such Board adoption. Any Options granted
hereunder prior to approval of the Plan by the stockholders shall be granted
subject to such approval and may not be exercised or realized, nor may Common
Stock be irrevocably transferred to any Participant, until and unless such
approval has occurred and the provisions of Section 9(a) have been satisfied.
Unless previously terminated, the Plan will terminate ten years and after
adoption by the Board, but such termination shall not affect any Stock Option
previously made or granted.

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