EXHIBIT 99(a)(12)
JOINT FILING AGREEMENT
In accordance with Rule 13d-1(f) under the Securities Exchange Act of
1934, as amended, each of the persons named below agrees to the joint filing
on Schedule 13D (including amendments thereto) with respect to the common
stock, par value $0.001 per share of Mycogen Corporation, a California
corporation, and further agrees that this Joint Filing Agreement be included
as an exhibit to such filings provided that, as contemplated by Section
13d-1(f)(1)(ii), no person shall be responsible for the completeness or
accuracy of the information concerning the other persons making such filings,
unless such person knew or had reason to believe that such information
is inaccurate. This Joint Filing Agreement may be executed in any number of
counterparts, all of which together shall constitute one and the same
instrument.
Dated: October 5, 1998 THE DOW CHEMICAL COMPANY
By: /s/ G. ▇▇▇▇▇▇▇ ▇▇▇▇▇
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Name: G. ▇▇▇▇▇▇▇ ▇▇▇▇▇
Title: Vice President and Controller
ROFAN SERVICES INC.
By: /s/ J. ▇▇▇▇▇ ▇▇▇▇▇▇▇▇
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Name: J. ▇▇▇▇▇ ▇▇▇▇▇▇▇▇
Title: President
CENTEN AG INC.
By: /s/ ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇
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Name: ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇
Title: President
DOW AGROSCIENCES LLC
By: /s/ ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇
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Name: ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇
Title: Vice President, Secretary and
General Counsel
AGROSCIENCES ACQUISITION INC.
By: /s/ ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇
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Name: ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇
Title: President