The resorptive vesicle of Temnocephala jheringi (Temnocephalida)

The wall of the resorptive vesicle is a merocrine secretor and a phagocytic syncytium, and its free plasma membrane shows deep and intertwined invaginations. Redundant foreign spermatozoa are engulfed by these invaginations, digested and incorporated into the individual's metabolism. The observations presented in this paper lead us to conclude that, during copulation, the resorptive vesicle acts as a temporary receptive organ for the foreign male gametes (bursa copulatrix role).