Spermatogenic cycle in seals (Callorhinus ursinus L.)

In the fur-seal germ cells at various stages of development are situated in the spermatic canaliculi as concentric layers in accordance with the stages of the spermatogenic cycle. By means of PAS-reaction 18 stages have been revealed in spermatogenesis of the fur-seal and basing on the first 15 of them, 15 stages of the spermatogenic cycles have been presented. Transformations of the nucleus during the process of spermatids development proceed similar to other animals studied, formation of acrosomes is accompanied with a specific for the given species development of temporal formation--tubulo-bulbar complexes, reduced at terminal stages of spermiogenesis.