EXHIBIT 10.3

                           NONSTATUTORY STOCK OPTION


_________________________, Optionee:

     MEGABIOS Corp. (the "Company"), pursuant to its 1997 Equity Incentive Plan
(the "Plan") has this day granted to you, the optionee named above, an option to
purchase shares of the common stock of the Company ("Common Stock").  This
option is not intended to qualify as and will not be treated as an "incentive
stock option" within the meaning of Section 422 of the Internal Revenue Code of
1986, as amended (the "Code").

     The details of your option are as follows:

     1.   The total number of shares of Common Stock subject to this option is
____________________ (__________).  Subject to the limitations contained herein,
this option shall be exercisable with respect to each installment of shares
subject to this option on or after the date of vesting applicable to such
installment.  The shares subject to this option shall vest as follows:

          (a) Twenty-five percent (25%) of the total number of shares subject to
this option shall vest one year after the Vesting Commencement Date, which is
______________ __, 19__; and

          (b) One thirty-sixth (1/36) of the remaining seventy-five percent
(75%) of the shares subject to this option shall vest at the end of each
additional one-month period following the vesting of the first 25% pursuant to
subsection (a) above.

     2.   (a)  The exercise price of this option is ___________________________
($___________) per share, being not less than 85% of the fair market value of
the Common Stock on the date of grant of this option.

          (b) Payment of the exercise price per share is due in full upon
exercise of all or any part of each installment which has accrued to you.  You
may elect, to the extent permitted by applicable statutes and regulations, to
make payment of the exercise price under one of the following alternatives:

               (i)   Payment of the exercise price per share in cash (including
check) at the time of exercise;

                                       1.

 
               (ii)  Payment pursuant to a program developed under Regulation T
as promulgated by the Federal Reserve Board which results in the receipt of cash
(or check) by the Company prior to the issuance of Common Stock;

               (iii) Provided that at the time of exercise the Company's
Common Stock is publicly traded and quoted regularly in the Wall Street Journal,
payment by delivery of already-owned shares of Common Stock, held for the period
required to avoid a charge to the Company's reported earnings, and owned free
and clear of any liens, claims, encumbrances or security interests, which Common
Stock shall be valued at its fair market value on the date of exercise; or

               (iv)  Payment by a combination of the methods of payment
permitted by subparagraph 2(b)(i) through 2(b)(iii) above.

     3.   This option may not be exercised for any number of shares which would
require the issuance of anything other than whole shares.

     4.   Notwithstanding anything to the contrary contained herein, this option
may not be exercised unless the shares issuable upon exercise of this option are
then registered under the Act or, if such Shares are not then so registered, the
Company has determined that such exercise and issuance would be exempt from the
registration requirements of the Act.

     5.   The term of this option commences on the date hereof and, unless
sooner terminated as set forth below or in the Plan, terminates on
_______________________ (which date shall be no more than ten (10) years from
the date this option is granted).  In no event may this option be exercised on
or after the date on which it terminates.  This option shall terminate prior to
the expiration of its term as follows:  three (3) months after the termination
of your employment with the Company or an affiliate of the Company (as defined
in the Plan) for any reason or for no reason unless:

          (a) such termination of employment is due to your permanent and total
disability (within the meaning of Section 422(c)(6) of the Code), in which event
the option shall terminate on the earlier of the termination date set forth
above or twelve (12) months following such termination of employment; or

          (b) such termination of employment is due to your death, in which
event the option shall terminate on the earlier of the termination date set
forth above or twelve (12) months after your death; or

          (c) during any part of such three (3) month period the option is not
exercisable solely because of the condition set forth in paragraph 4 above, in
which event the option shall not terminate until the earlier of the termination
date set forth above or until it shall have been exercisable for an aggregate
period of three (3) months after the termination of employment.
 

                                       2.

 
     However, this option may be exercised following termination of employment
only as to that number of shares as to which it was exercisable on the date of
termination of employment under the provisions of paragraph 1 of this option.

     6.   (a)  This option may be exercised, to the extent specified above, by
delivering a notice of exercise (in a form designated by the Company) together
with the exercise price to the Secretary of the Company, or to such other person
as the Company may designate, during regular business hours, together with such
additional documents as the Company may then require pursuant to subparagraph
11(e) of the Plan.

          (b) By exercising this option you agree that:

                (i)   the Company may require you to enter an arrangement
providing for the cash payment by you to the Company of any tax withholding
obligation of the Company arising by reason of: (1) the exercise of this option;
(2) the lapse of any substantial risk of forfeiture to which the shares are
subject at the time of exercise; or (3) the disposition of shares acquired upon
such exercise; and

                (ii)  the Company (or a representative of the underwriters) may,
in connection with the first underwritten registration of the offering of any
securities of the Company under the Act, require that you not sell or otherwise
transfer or dispose of any shares of Common Stock or other securities of the
Company during such period (not to exceed one hundred eighty (180) days)
following the effective date (the "Effective Date") of the registration
statement of the Company filed under the Act as may be requested by the Company
or the representative of the underwriters. For purposes of this restriction you
will be deemed to own securities which (i) are owned directly or indirectly by
you, including securities held for your benefit by nominees, custodians, brokers
or pledgees; (ii) may be acquired by you within sixty (60) days of the Effective
Date; (iii) are owned directly or indirectly, by or for your brothers or sisters
(whether by whole or half blood) spouse, ancestors and lineal descendants; or
(iv) are owned, directly or indirectly, by or for a corporation, partnership,
estate or trust of which you are a shareholder, partner or beneficiary, but only
to the extent of your proportionate interest therein as a shareholder, partner
or beneficiary thereof. You further agree that the Company may impose stop-
transfer instructions with respect to securities subject to the foregoing
restrictions until the end of such period.

     7.   This option is not transferable, except by will or by the laws of
descent and distribution or pursuant to a qualified domestic relations order as
defined in the Code or Title I of the Employee Retirement Income Security Act (a
"QDRO"), and is exercisable during your life only by you or a transferee
pursuant to a QDRO.

     8.   This option is not an employment contract and nothing in this option
shall be deemed to create in any way whatsoever any obligation on your part to
continue in the employ of the Company, or of the Company to continue your
employment with the Company.  In the event that this option is granted to you in
connection with the performance of services as a consultant or director,
references to employment, employee and similar terms shall be deemed

                                       3.

 
to include the performance of services as a consultant or a director, as the
case may be, provided, however, that no rights as an employee shall arise by
reason of the use of such terms.

     9.   Any notices provided for in this option or the Plan shall be given in
writing and shall be deemed effectively given upon receipt or, in the case of
notices delivered by the Company to you, five (5) days after deposit in the
United States mail, postage prepaid, addressed to you at the address specified
below or at such other address as you hereafter designate by written notice to
the Company.

     10.  This option is subject to all the provisions of the Plan, a copy of
which is attached hereto and its provisions are hereby made a part of this
option, including without limitation the provisions of paragraph 6 of the Plan
relating to option provisions, and is further subject to all interpretations,
amendments, rules and regulations which may from time to time be promulgated and
adopted pursuant to the Plan.  In the event of any conflict between the
provisions of this option and those of the Plan, the provisions of the Plan
shall control.

     Dated the ____ day of __________________, 19__.

                                        Very truly yours,

 
                                        ____________________________________


                                        By _________________________________
                                            Duly authorized on behalf
                                            of the Board of Directors

ATTACHMENTS:

     1997 Equity Incentive Plan
     Notice of Exercise
 

                                       4.

 
The undersigned:

     (a) Acknowledges receipt of the foregoing option and the attachments
referenced therein and understands that all rights and liabilities with respect
to this option are set forth in the option and the Plan; and

     (b) Acknowledges that as of the date of grant of this option, it sets forth
the entire understanding between the undersigned optionee and the Company and
its affiliates regarding the acquisition of stock in the Company and supersedes
all prior oral and written agreements on that subject with the exception of (i)
the options previously granted and delivered to the undersigned under stock
option plans of the Company, and (ii) the following agreements only:

     NONE     ____________________
               (Initial)

     OTHER    ____________________________________
              ____________________________________
              ____________________________________


                                ________________________________________ 
                                OPTIONEE

                                Address: _______________________________
                                         _______________________________ 

                                       5.