Ultrastructure of epididymal spermatozoa of the Asiatic Musk Shrew, Suncus murinus.

The ultrastructure of epididymal spermatozoa of the insectivore, Suncus murinus, is described. The acrosome of Suncus spermatozoa is noteworthy for its size. It is an elongate flattened structure 21.5 Mm long, 17.5 pm at its greatest width and 1 Mm thick. The nucleus is also flattened and bears a definite indentation that marks the posterior limit of the acrosome. The midpiece is long and possesses more than 100 mitochondrial gyres. The dense outer fibers of the midpiece show bilateral rather than radial symmetry, the bilateral symmetry being achieved from an odd number of fibers as a result of pronounced lobation of one of the fibers.