CYTOLOGICAL TECHNIQUE 



intercellular space 



centriole 



lipid ground cytoplasm 



globules (in wide sense) 



idiozome 

 \ 



nucleolus 



centromere 



heterochroma tic 



segment of 

 chromosome 



euchromatic segment of 



chromosome 

 uJ 



Wjj 



Fig. 1. A typical spermatogonium, seen in optical section. The figure 

 is intended to show the structure of the living cell. Compare with 

 fig. 4, p. 26. {The contents of the nucleus are represented diagram- 

 matically; the rest of the figure is based on the spermatogonium 

 of the common newt, Triturus vulgaris.)^* 



considered. The nucleus will be taken first, but it will be con- 

 venient to describe the rest of the inclusions in a different order 

 from that given above, mainly because the idiozome is such a 

 striking object in typical spermatogonia. 



The nucleus is the largest single cytoplasmic inclusion in most 

 cells. In spermatogonia it is commonly eccentric (fig. 1), and this 



