552 



These nuclei are imbedded in a noass of cytoplasm without cell boun- 

 daries and amitoses are of frequent occurrence. In this stage of testis 

 development no case of mitosis has ever been observed. Figure 3 

 represents two adjoining testes in an early stage of development. 



Somewhat later some of the smaller nuclei, apparently either from 

 the testis itself or from the surrounding parenchyma arrange themselves 

 about the others and the follicle and vas eff'erens differentiate. Within 

 the testis amitosis continues (Fig. 4 a, b, c). Occasionally mitosis is 

 found in testes of this stage, but it is very rare, usually not more 

 than four or five cases being found in a whole proglottid which may 

 contain hundreds of testes. It has never been seen before the follicle 

 is fully formed and the testis consists of a considerable number of 

 nuclei, and then only in isolated cases, one in a testis. Amitosis con- 

 tinues even in the same testis where mitosis is going on (Fig. 5 a, a 



Fig. 4. 



Fig. 5. 



somewhat later stage). It is of interest to note that during mitosis 

 the dividing cell becomes marked off by a distinct membrane from the 

 remainder of the testis which is still more or less completely syncytial 

 (Fig. 5). 



In Figure 6, a still later stage, the nuclei of one part of the 

 testis are smaller and are apparently dividing more rapidly than the 

 larger nuclei. This is an early stage of a differentiation which appears 

 in many cases. These smaller nuclei or a part of them undergo de- 

 generation and later form a deeply staining mass which is apparently 

 gradually absorbed by the remaining cytoplasm. The number of de- 

 generating nuclei and their position vary greatly. Sometimes they are 



