Pseudohermaphroditism in Ilyanassa obsoleta (Mollusca: Neogastropoda).

Field studies, a rearing and maintenance program, and a transfer experiment have shown that anomalous male traits found in some female Ilyanassa obsoleta are an expression of environmentally controlled psuedohermaphroditism. The particular pattern of pseudohermaphroditism discovered in this species has not been reported previously from any other group, but may be characteristic of the Neogastropoda.