Atypical Spermiogenesis in Thermobia domestica, a Thysanuran Insect

Abstract

IN a recent communication, Bawa1 has again put forward the hypothesis of a typical sperm in Thermobia domestica. However, I have shown2, with some electron photographs of Petrobius maritimus, that the centriole and the acrosome are in their normal positions. The acrosome is a scoop-shaped body at the anterior end of the nucleus which forms a projecting tube. What Bawa has called the acrosome is probably another body, the centriole adjunct3, which encloses a centriole and gives rise to the flagellum. In Thysanura, no division of the centriole occurs, and as such it is a fixed body on the posterior aspect of the nucleus. These observations are further strengthened by the detailed cytochemical reactions obtained by me, the results of which will be published elsewhere.