The behaviour of centrioles and the formation of the flagellum in rooster and drake spermatids.

Developmental changes in the formation of the centrioles and flagellum during spermiogenesis in the rooster and drake were studied. Changes in the length and thickness of the wall of the centrioles were observed from an early stage of spermatid development. Before the proximal centriole is attached to the nucleus microtubules were observed near the centrioles joined to them. At this stage of spermatid development changes on the nuclear membrane were observed at a place where the proximal centriole is attached to the nucleus. At the later stage of spermatid differentiation three to five dense extensions in the space of the nuclear invagination and dense bodies or granules near the distal centriole were present. The anterior part of the newly formed flagellum is covered by a cytoplasmic membrane displaying extension which is approximately 1.3 mum long. Slight differences between the two species were observed.