126 J. T. CUNNINGHAM. 



long. These germ-cells are about 8 ^ in their larger diameter, 

 but some of them are somewhat larger. Around them can be 

 seen the small nuclei of the ordinary non-germinal epithelial 

 cells, which in most cases extend over the surface of the groups 

 of germ-cells. The epithelium in the intervals between the 

 spots where germ-cells are seen appears to be only one cell 

 thick, and the cells composing it are extremely small. They 

 are not, however, so flat and thin as they are in other condi- 

 tions of the ovary, but show some thickness in section. 



Some of the sections now under consideration are from 

 material fixed with corrosive sublimate and acetic, some from 

 material fixed with the strong mixture of Flemming. In none 

 can I distinguish actual figures of mitotic division in the germ- 

 cells, although I am strongly inclined to hold that vom E,ath's 

 view is correct, that the germ-cells always divide by typical 

 mitosis. I have seen division figures in these cells in the 

 germinal epithelium of Myxine and Conger. The preparations 

 of the generative organ of Myxine to which I refer were 

 obtained from very young specimens, in which the organ was 

 a very thin narrow fold. It contained anteriorly minute eggs, 

 .and in the posterior part small testicular capsules. The 

 material was fixed in Flemming's mixture, the sections stained 

 with hsematoxylin. The germinal epithelium in these Myxine 

 sections is limited to the extreme edge of the genital lamina, 

 and in section is somewhat crescentic. It is several cells 

 deep, but the cells are irregularly arranged, and are poly- 

 gonal in shape, not flattened. The germ-cells in the resting 

 state are about 13 fx in diameter, the greater part of which is 

 taken up by the nucleus ; the interstitial cells are somewhat 

 smaller. 



No investigator appears yet to have traced out completely 

 the division of the germ-cells in the germinal epithelium of the 

 vertebrate ovary, and their conversion into definite ova 

 surrounded with follicle cells. Vom Rath figures only two 

 sections, one of the ovary of a young female Salamander, one 

 of an undiff'erentiated reproductive ridge of the same animal. 

 In the former the structure represented seems to me to corre- 



