Studies on the Spermiogenesis of Siphonaria laciniosa (Gastropoda, Pulmonata) from the Gulf of Aqaba. 1. Nuclear Changes PDF

Keywords

spermiogenesis, electron microscopy, nucleus

Abstract

The spermiogenesis of Siphonaria laciniosa (Gastropoda, Pulmonata) was studied by electron microscopy. Some of the most drastic changes comprising the process of spermiogenesis involve the nucleus which undergoes a series of changes affecting its shape, size, differentiation of various regions of its envelope, and progressive condensation of its chromatin. Active nucleo-cytoplasmic exchange seems to take place in the various phases of the process especially in its early stages. The various shapes acquired by the nucleus are described in detail, and are taken as salient points in the continuous process of spermiogenesis. These stages are: the "urn" stage; the" hammer head" stage; the "hazel-nut" stage; and the "spearhead" stage. Many of the morphological transformation exhibited by the nucleus, especially those of the later phases of spermiogenesis are effected by microtubules.