THE SrERM.VTOOENESLS OF IX)ME.ST1C MAXI.\IAr>S. 213 



As tlie spindles cau not clearly bo seen, it is difficult to determine 

 directly tlu \x)int of attaclimenb of tbo spindle fiber. It is, however, con- 

 ceivable that, if (lie sjjiiidlo fiber attaches to the end of a chromosome, tho 

 daughter chromosomes iu tho anaphase must assume straight rod-shape. For 

 this reason it seems certain that in the mouse the spindle fibers must atfcxch 

 to the ends of the clu'omosomes. Allen ('18) also proposed the sjime view 

 in the rat, where he says : " It will be of interest to learn if it is chai'ac- 

 teristic of rodents or peculiar to the rat." 



In the preparation stained with Auerbach's method a cytoplasmic mass 

 can usually be found in close contact to the nuclear wall, while in Heiden- 

 hain's method nothing can be seen in the cytoplasm (Fig. 127). Although 

 tliis mass is not so conspicuous as the idiozome in tlie spermatocyte, its 

 appearance and its situation coiTcspyud almost exactly with those of the latter 

 cells, so tliat I do not hesitiite to identify it with the same. Ddesberg ('08) 

 and Allen ('18) have not found the idiozomj in the spermatogonia of the 

 rat. 



The mitochondrial granules appear in tho cytoplasm, being scattered 

 throughout the latter (Fig. 6). The amoimt seems t.j be the same as those 

 of the young spermatocyte. In the metaphase they remain imdivided and lie 

 outside the spindle (Fig. 6). After the cell is divided into two the mitochon- 

 drial granules seem to be eciiuxlly distributed in the cytoplasm of the daughter 

 sells. The size of the granules appears to be smaller than that in the 

 prophase of the first reduction division. 



B. The spermatogonia in the rabbit. 



As in the m(jiLse, we can distinguish S3veral kinds of spermatogonia! 

 cells which are probably of different generations (Figs. 85-87). The resting 

 nuclei of the spermatogonia! celLs usually contain many chromatin masses 

 (karyosomes) and several nucboli wliich can clearly be seau iu the sections 

 stained with Auerbach's method (Fig. 145). 



During the early prophase many chromatin masses appear which gi'adually 

 elongate and form the fine chromatin spiremes (Figs. 85, 86). Soon after 

 the spiremes become thicker and are convoluted throughout the nucleus 

 (Figs. 85, 86). At this stage nucleoli cau not be seen at all (Fig. 86). In 



( 



