The observations reported herein are part of an extensive study of the biology of Urosalpinx cinerea (Say), the smooth oyster drill, and Eupleura caudata (Say), the rnugh oyster drill, which is in progress at our laboratory. Results of studies of other aspects of the behavior and ecology of these predatory snails will be reported as they become available.
Little is known of the copulatory behavior of dioecious marine gastropods. Though Stauber (1943) reported a partial pairing of E. caudata, pairing of U. cinerea has never been described. Our studies show that pairing of both species is a complex process involving fairly intricate behavior of both sexes
