definiens: means the period beginning on the EFFECTIVE DATE and ending onlMarch 31.1999 ; provided . however . that MERCK may extend the OPTION PERIOD with respect to the use of \,plasmid DNA within the FIELD fOl\two ( 2 ) three ( 3 ) month pedads ( endinglJune 3D, 1999 and, September 30,1999 ) upon written " otieeto BIOJECT and by paying BIOJECTlsix - hundred thousand dollars ( U.S. ) ( $ 600.000.DO } for the first of such extension periods and{!ne wilUoR dO!!6rn ( ! ! § ) ( $ 1 999 990.pm for " the second of such extension periods . The first of any such extension payment shail be due by\March 31 J 1999 and the second of any such -extension payment shall be due bYlJune 30, 1999 . These payments shall be made by wire transfer to a bank to be deSignated by BIOJECT