EXHIBIT 4.1 SPECIMEN OF COMMON STOCK M(TM) MYCOGEN CORPORATION THIS CERTIFICATES IS TRANSFERABLE INCORPORATION UNDER THE LAWS OF THE STATE OF CALIFORNIA SEE REVERSE FOR STATEMENTS RELATING IN BOSTON, MA OR NEW YORK, NY TO RIGHTS, PREFERENCES, PRIVILEGES AND RESTRICTIONS, IF ANY - ------------------------------------------------------------------------------------------------------------------------------------ This Certifies that CUSIP 628452 10 4 SPECIMEN is the record holder of - ------------------------------------------------------------------------------------------------------------------------------------ FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, $.001 PAR VALUE PER SHARE, OF -------------------------------------------MYCOGEN CORPORATION------------------------------------- -------------------------------------------------- -------------------------------------------- ------------------------------------------- ------------------------------------- transferable only on the books of the Corporation by the holder hereof in person or by duly authorized Attorney upon surrender of this certificate properly endorsed. This certificate is not valid until countersigned by the Transfer Agent and registered by the Registrar. WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. Dated COUNTERSIGNED AND REGISTERED: THE FIRST NATIONAL BANK OF BOSTON TRANSFER AGENT AND REGISTRAR BY /s/ M. Denzic AUTHORIZED SIGNATURE /s/ Carlton J. Eibl /s/ Jerry Caulder SPECIMEN [STAMP OF MYCOGEN CORPORATION APPEARS HERE] SPECIMEN SECRETARY CHAIRMAN OF THE BOARD A statement of the rights, preferences, privileges and restrictions granted to or imposed upon respective classes or series of shares and upon the holders thereof as established, from time to time, by the Articles of incorporation of the Corporation and by any certificate of determination, and the number of shares constituting each class and series and the designations thereof, may be obtained by the holder hereof upon written request and without charge from the Secretary of the Corporation at its corporate headquarters. This certificate also evidences and entitles the holder hereof to certain rights as set forth in an Amended and Restated Rights Agreement between Mycogen Corporation and The First National Bank of Boston dated as of October 19, 1995 (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 Mycogen Corporation. Under certain circumstances, as set forth in the Rights Agreement, such Rights will be evidenced by separate certificates and will no longer be evidenced by this certificate. Mycogen Corporation will mail to the holder of this certificate a copy of the Rights Agreement without charge after receipt of a written request therefor. Under certain circumstances, as set forth in the Rights Agreement, Rights Issued to any Person who becomes an Acquiring Person (as defined in the Rights Agreement) may become null and void. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations: TEN COM -- as tenants in common UNIF GIFT MIN ACT -- ................ Custodian ................. TEN ENT -- as tenants by the entireties (Cust) (Minor) JT TEN -- as joint tenants with right of under Uniform Gifts to Minors survivorship and not as tenants Act ........................................ in common (State) UNIF TRF MIN ACT -- ............. Custodian (until age ........) (Cust) .................... Under Uniform Transfers (Minors) to Minors Act .............................. (State) Additional abbreviations may also be used though not in the above list. FOR VALUE RECEIVED,__________________ hereby sell, assign and transfer unto PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE ______________________________________ ______________________________________ ________________________________________________________________________________ (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE) ________________________________________________________________________________ ________________________________________________________________________________ __________________________________________________________________________Shares of the capital stock represented by the within Certificate, and do hereby irrevocably constitute and appoint ________________________________________________________________________Attorney to transfer the said stock on the books of the within named Corporation with full power of substitution in the premises. Dated_____________________________ X___________________________________________ X___________________________________________ THE SIGNATURE(S) TO THIS ASSIGNMENT MUST NOTICE: CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR. WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER. Signature(s) Guaranteed By_____________________________________________________ THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM). PURSUANT TO S.E.C. RULE 17Ad-15.