The Preputial Organ of Snails in the Genus Helisoma (Gastropoda: Pulmonata)

Abstract

Observations on mating showed that the penial complex of the snail is everted in order that the process of mating becomes possible. While the snails are mating the preputial organ adheres firmly to the neck of the same snail thus acting as a brace and helping to produce leverage. Also, by pushing the twisted head-foot region aside it provides a space for the verge to reach the vagina. A large number of flask-shaped cells present in the epithelium lining the verge sac provide the latter and the ver,ge with their needed secretions. Consequently, secretions from the compound tubular glandular epithelium of the preputial organ have little or no effect on rendering these structures moist but, apparently help in dilating the aperture in the center of the diaphragm. A papilla at the end of the verge has a hard fibrous area at its tip. This papilla functions as an excitatory organ.