THE ULTRASTRUCTURE OF THE SPERMATOZOA OF SQUAMATA .1. SCINCIDAE, GEKKONIDAE AND PYGOPODIDAE (REPTILIA)

Squamate autapomorphies seen in sperm of the Scincidae (e.g. Ctenotus robustus, Carlia pectoralis, Crytoblepharus virgatus, and Lampropholis delicata) are penetration of the fibrous sheath of the axoneme into t he midpiece, and the paracrystalline subacrosomal cone. Sphenomorphus group spermatozoa (e.g. Ctenotus) and the Egernia group (Tiliqua) diff er from the more derived Eugongylus group (C. virgarus, L. delicata an d C. pecioralis) in that the acrosome is elongate and apically depress ed; the perforatorium is strongly oblique; the midpiece is relatively short, with four dense ring structures in longitudinal succession; mit ochondria are columnar; and enlarged peripheral fibres 3 and 8 do not show the gross anterior enlargement seen in Carlia and Lampropholis. H eteronotia binoei (Gekkonidae) sperm have no epinuclear electron-lucen t region; nuclear shoulders are smooth, as in sphenomorph but not Eugo ngylus group skinks; mitochondria are columnar; unlike skinks, the med ian surfaces of the mitochondria are indented by triangular, sometimes longitudinally, interconnected dense bodies. In Lialis burtonis (Pygo podidae) sperm, the perforatorium extends virtually to the tip of the fore-shortened apically domed acrosome; nuclear shoulders are absent; the mitochondria alternate singly or in groups with one or more dense bodies which also form an interrupted collar around the distal centrio le. Spermarozoal ultrastructure suggests that a common ancestry of sna kes and pygopods deserves consideration.