UNIQUE CASE OF CYTODIFFERENTIATION - SPERMIOGENESIS OF THE PRAWN, PALAEMONETES-PALUDOSUS

The sperm of the prawn, Palaemonetes paludosus, has an atypical form consisting of a cup-shaped nucleus and a rigid cross-striated spike extending from the convex side of the nucleus. The nucleus contains many membrane-bound, PAS-positive vesicles. During spermiogenesis, stacks of lamellar structures are located along the outer layer of the nuclear envelope. These lamellar stacks become associated with ribosome-like particles, after which small sheets of material pass from the lamellar stacks and form the striated spike. The excess lamellar membranes are extruded from the cell. The membrane bound-vesicles in the nucleus may arise by the process of pinocytosis of the sustentacular cell cytoplasm and of the material from the lumen of the vas deferens. © 1979 Academic Press, Inc.