298 L. J. BACHHUBER. 



identified although some of the more granular parts of the 

 cytoplasm may include the centrosome and the chromatoid body. 

 This is however doubtful because the staining reactions given 

 by these structures in the primary and secondary spermato- 

 cytes ought also be given in the spermatogonia. 



Only one spermatogonial stage has been found in which the 

 chromatoid body appeared to be present (Fig. 6). While it has 

 the characteristic appearance of this body, it is a rather doubtful 

 case because it could not be identified in any other of the sperma- 

 togonial stages. 



As development continues, dense masses of chromatin appear 

 concentrating along the radial linin threads. These masses 

 vary in number, but never exceed the diploid number of chromo- 

 somes, making it highly possible that these masses later trans- 

 form into the univalent chromosomes. The entire nucleus stains 

 heavily with the basic dyes, indicating a large increase of the 

 chromatin content of the cell. In this manner, from twelve to 

 twenty-two masses of chromatin are formed, all united by heavy 

 linin threads. Gradually the linin threads disappear, and the 

 chromatin masses assume a more regular appearance (Fig. 7). 

 The nuclear wall disintegrates as the chromosomes arrange them- 

 selves in the metaphase stage (Fig. 8). The spindle fibers are 

 very indistinct although in favorably stained sections they may 

 be made to stand out more strongly. Because of this excess 

 of stain, the cells which were stained heavy enough to make the 

 spindle fibers appear more plainly were useless for the study 

 of any of the other structures. 



The chromosomes at best tend to mass together, and if not 

 strongly destained, form a huge black mass in which nothing 

 can be distinguished. In some of the metaphase stages it is 

 possible to count twenty-two chromosomes (Figs. 8, 9, 10). 

 The X and the Y elements which are shown to exist from their 

 subsequent behavior, could not be distinguished from each 

 other or from the remainder of the chromosomes in the spermato- 

 gonial division stage. It appears probable that the two large 

 karyosomes present in the early spermatogonial stages may 

 represent the accessory elements because they retain their 

 individuality and later appear to transform directly into two 



