Atypical spermatogenesis in Murex brandaris.

Atypical spermatogenesis in Murex brandaris occurs in specific areas of the testis. In the early stages, a large nucleus is apparent, together with highly electrodense drops of chromatin spread through the caryoplasm. Many mitochondria are observed at one point of the cytoplasm, and numerous centrioles appear. In the following stages, vacuolization and degeneration of the chromatin are apparent, producing half moon-shaped chromatinic bodies called "caryomerites." Some degeneration of the chondrioma occurs too. Later, the chromatin degenerates and the centrioles produce cilia, while the Golgi body, highly secretory at this stage, produces electrodense PAS- as well as Thiery-positive granules. Moreover, a vermiform-shaped anuclear ciliated cell with numerous electrodense cytoplasmic granules is observed in the M. brandaris atypical spermatozoon.