SPERMATOGENESIS OF PASSALUS CORNUTUS. 417 



Giinthert (1910) has described similar results in the differ- 

 entiation of nurse cells and oocytes in Dytiscus and Govaerts 

 (1913) has done likewise in Carabiis. In Passalus, it is only in 

 the region of the cell-plate that the spindle takes the basic stain. 

 In cross-section the spindle remains appear as plasmasome-like 

 bodies in the cytoplasm. Often there may be seen deeply stain- 

 ing granules adhering to the surface of such bodies; these I take 

 to be portions of the deeply-staining cell-plate. 



2. Spermatocytes. The spindle remains of the last spermato- 

 gonial division (together with the cell-plate) persist into the 

 spermatocyte and remain very conspicuous throughout the 

 entire growth period (Figs. 6, 8, 27). Every spermatocyte 

 exhibits these spindle remains, either in their original positions 

 connecting cells or else in the form of plasmasome-like bodies 

 lying free in the cytoplasm. Similar conditions have been shown 

 by Voivnov in Cybister and by Munson in Papilio. In Gryllo- 

 talpa, Payne states that "there is no indication that a sphere or 

 the spindle and astral fibers persist after cell-division." In 

 his figure B, plate i, he shows two plasmasome-like bodies present 

 in the cytoplasm of a spermatocyte during the early growth 

 period. As to the origin of these bodies, he is uncertain, but 

 he is not ready to admit that they may be idiozome material. 

 I agree that it would be rather speculative to assign the term 

 "idiozome" to these bodies, but in Passalus it is quite clear 

 that similar bodies are derived from the spindle. I am not 

 able to establish the presence of a definite "idiozome" or sphere 

 material in the spermatocytes of Passalus and just where the 

 centrosomes lie hidden during the growth period is a difficult 

 matter to determine. Since the cells are so filled with mito- 

 chondria at this time, it seems almost impossible to definitely 

 locate them. The centrosomes are first discernible when the 

 first maturation spindle makes its appearance. From the long 

 persistence of the spindle remains of the last spermatogonial 

 division, it may be concluded that its substance must be of 

 some inert, resistant material. Munson (1906, p. 90) makes the 

 following remarks on Papilio: 



"The resistance of the maturation spindles to reagents is 

 remarkable. In studying the living dividing cells on the slide, 



