O. C. GLASER. 



which in the preserved specimens studied have the appearance of 

 a more or less definite reticulum suspended in a homogenous 

 ground substance. The vesicles are bounded by a definite mem- 

 brane outside of which is granular cytoplasm with large yolk 

 spheres. It is quite evident from the legend beneath Fig. 6, p. 

 875, of Professor Osborn's paper ('04) that he misinterpreted what 

 he saw, for he figures the germinal vesicle alone, and says that 



it is " The nucleus and the 

 immediately adjacent cyto- 

 plasm," mistaking the nu- 

 cleolus for the nucleus, and 

 the non-staining portion of 

 the vesicle for cytoplasm. 



After the food ova have 

 been ingested a number of 

 days, the germinal vesicles 

 fragment, and the appear- 

 ance which they present at 

 that time is much as though 

 they had exploded. Instead 

 of finding a single nucleus, 

 one sees numerous frag- 

 ments, varying greatly in 

 size, and in each case, mini- 

 atures of the original ger- 

 minal vesicle. Each frag- 

 ment has a central mass, 

 frothy in structure, and 

 staining deeply in the 

 spaces, between the bubbles 

 — a piece of the original 

 nucleolus. Surrounding this stained region, is a clear zone of 

 finely granulated nuclear substance bounded by a definite mem- 

 brane. In some cases the " nucleoli " of these fragments are 

 irregular, but usually their outlines are oval and smooth. 



I have not been able to find the elongated dumb-bell shapes 

 described by Osborn ('04, Fig. 7), and interpreted by him as late 

 stages in amitosis ; neither have I succeeded in satisfying myself 

 that such intermediate stages as my material shows, are common 



Fig. 2. Fragments of two germinal vesicles 

 The large black bodies represent yolk. 



