The first collection of oyster for this study was taken off Fulton Beach, Aransas Bay on January 1, 1962. Subsequently, 34 collections were made, most of them in Aransas Bay, but several collections were made in Mesquite, Tres Palacios, Corpus Christi, and Galveston Bays. These oysters were sectioned and slides made, a total of more than 1300. All collections were of live oysters, and the reading of the slides was a slow process. Live oysters were used because the platforms which were to hold trays of oysters were delayed in construction. Hence, no data on mortality are available. The period from January 1, 1962, to June 26, 1962, was used to determine roughly from the slides what parasites and diseases were present and where they were located. The data on collections are listed in Table 1
