551 



My observations indicate that each testis arises in situ from one 

 or two, or possibly in some cases more nuclei. The nuclei or the cells 

 — if they can be called such in their syncytial condition — from 

 which they arise do not 

 ditfer visibly from other 

 branched cells of the par- 

 enchyma. Figure 2 A and 



B represent two "cells" in ^x . 



the zone where testes ap- j ^1 ', f %\ 



pear, and at the stage when \ \^ ^ ) / ^ V J 



they are forming. These V — J ; 



are probably the mother- ; r 



cells of testes but there is 

 no way of determining cert- 

 ainly whether single nuclei Fig. 2. 

 will give rise to testes, since 



they dififer in no way from the surrounding nuclei. In this case other 

 testes sufficiently far advanced in development to be already recogni- 

 zable adjoined these two cells. The nucleus in Figure 2 A is dividing. 



Fig. 3. 



The earliest stage at which the testis becomes distinguishable with 

 certainty is when it consists of two or three or more nuclei (Fig. 3). 



