Cytoplasmic whorls in the golden hamster oocyte.

Fragments of 40 ovaries of various laboratory mammals, including mice, golden hamsters, rabbits and ferrets have been studied. The structures described in this paper were observed in some of the oocytes in the 14-day-old golden hamster ovary. The specimens in which they were present were obtained from 4 animals. After fixation for 60 min in chilled, buffered osmium tetroxide, the blocks were dehydrated in a graded series of alcohols and embedded in Epon 812 (Luft, 1961). Sections were cut on a Porter-Blum microtome and studied in an RCA EMU 3 F-2 electron microscope. To increase contrast, sections were stained with either uranyl acetate or lead citrate (Reynolds, 1963).