MORPHOLOGY OF THE HEMIPENES OF SOME AMPHISBAENIA (REPTILIA, SQUAMATA)

Preserved amphisbaenids with fully everted hemipenes are rare and few studies have described these intromittent organs in detail. Some previous descriptions are misleading as they are based on partially everted hemipenes. In this paper the hemipenes of several species of amphisbaenids are described on the basis of gross anatomical, histological, and scanning electron microscopy observations. Study of a series of specimens of Amphisbaena caeca and of A. innocens indicates that many hemipenes were not fully everted during fixation. The typical amphisbaenian hemipenis consists of a main truncus that bifurcates to form two lobes. The distal tips of the lobes may bear fields of lamellae that surround the termination of the sulcus spermaticus. Various regions of the outer surface of the lobes may also bear microornamentation. Some possible roles of lamellae and papillae during copulation are discussed.