10 



parts, and consider their relation to each other. 



In Figs. 37 to 41 the shape of the nucleus may he some- 

 T?hat modified by strains In the cytoplasm or by the crowding 

 of the elements in the tubule. In these drawings there is 

 no evidence of a granular or reticular structure, although 

 such structure was made out in some preparations which were 

 destained to a greater degree. In Fig. 37 It may be observed 

 that the outer layer of the nucleus stains more densely than 

 the inner portion. The nucleus in Fig. 38 contains a vacuole 

 which does not take the stain. The cytoplasm surrounding the 

 nucleus and capsule in Figs. 37 to 39 Is nearly uniform in 

 appearance, with probably a tendency to be a little more deep- 

 ly stained near the nucleus. In Figs. 40 and 41 there is a 

 concentration of a portion of the cytoplasm on one side of the 

 capsule and bordering the nucleus. This is finely alveolar 

 and stains more deeply than the rest of the cytoplasm. It 

 may be that this patch of cytoplasm is seen in an earlier 

 stage In Fig. 36c. This portion of the cytoplasm crowds in 

 between the nucleus and the capsule (Fig. 42). About this 

 time the capsule begins to take a brownish color when stain- 

 ed with iron-haematoxylin. 



The otigin and development of this portion of cytoplasm 

 which appears on the side of the capsule and nucleus and 

 wedges in between them is a striking feature In the develop- 

 ment of the sperm. Its behavior is well brought out in Figs. 

 45-48. In Fig. 45 we see this substance slipped in like a 

 wedge between the nucleus and the capsule with a clear space 

 between it and the nucleus. If the spermatid shown in this 



