THE MITOCHONDRIA AND OTHER STRUCTURES. I 03 



made as controls, but they were not so useful for the study of the 

 cell structure owing to the fact that the medium is more opaque 

 and that the cells do not spread out in a thin layer close to the 

 cover slip. Also the plasma medium is more difficult to use for 

 experimental purposes owing to the fact that it is easily coagu- 

 lated. 



OBSERVATIONS. 



General. When the cyst wall is broken the cells flow out and 

 become attached to the cover slip. The cells appear to be formed 

 of a clear homogeneous cytoplasm which contains a nucleus and 

 granules. Numerous cells, which contain two or four nuclei 

 and also a correspondingly increased amount of mitochondria, 

 were observed in all stages of development as, for instance, a 

 first spermatocyte with two nuclei and a double amount of 

 mitochondria or a young spermatid with two or four nuclei and 

 also two or four nebenkern. During observations upon one 

 unstained preparation two second spermatocytes whose cyto- 

 plasm touched at one point were observed to fuse into a single 

 cell (Figs. 27, 28, 29). The fused cell, which resulted from the 

 two single cells, contained two groups of chromosomes and two 

 groups of mitochondria. In certain stages in the development 

 of the germ cell the granules are scattered throughout the greater 

 part of the cytoplasm (spermatogonium), while in other stages 

 the granules are limited to a definite area (division of spermato- 

 cytes). There is no indication of any network structure either 

 of the cytoplasm or of the nucleus. The cells of a cyst remain 

 attached to each other by a long thread-like process, or in some 

 cases by a short thick process, which appears as though the cells 

 had not been completely separated at division, but had remained 

 attached by a band of cytoplasm. Groups of spermatozoa are 

 attached by one end to a crescent-shaped body, while the other 

 end is free and lashes about continuously. Several of these 

 crescent-shaped bodies, each with numerous spermatozoa at- 

 tached to it, may be seen in one field. The cells may send out 

 broad, flat pseudopodia and crawl along the cover slip, or in 

 media which are too concentrated or to which Janus green has 

 been added, the cells may send out numerous delicate pseudo- 

 podia, which appear more like flagella. However, other factors 



