Spermiogenesis in the Crayfish (Procambarus Clarkii)

Dr. Moses' present address is the latter Aflagellate sperm were first described in detail in 1878 by Grobben (6), but they have remained poorly understood despite efforts to homologize them with flagellate types.It would appear from the confusion in the literature that these unique forms are not to be forced into a mold.The weakness of such attempts rests mainly in the uncertain specificity of staining methods for identifying mitochondria, Golgi elements, centrioles, etc., and their derivatives.Indeed, even the nucleus was not positively identified until the Feulgen reaction was applied to crayfish sperm by Mc-Croan in 1938 (9).The electron microscope, es-pecially when carefully combined with closely correlated light microscopy and cytochemistry, provides a fresh and more certain approach to the kind of problem in cellular differentiation presented by the aflagellate sperm.Utilizing this approach, we have investigated the morphology and genesis of several types of aflagellate sperm, a study which is still in progress.Some of our results, particularly concerning the sperm of the crayfish, have already been presented at meetings and have been published in brief (10)(11)(12).This is the first report depicting and characterizing the morphology of the mature