224 MICHAEL F. GUYER. 



The matter of counting the spermatogonial chromosomes, it 

 must be admitted, is one of great difficulty. In the late prophase 

 or equatorial plate stage, the only time at which a count is possible, 

 they lie for the most part in an irregular band around a central 

 clearer area. In the vast majority of cases only a deeply stained 

 mass of small contiguous or overlapping chromosomes is visible 

 in this band and an accurate count is out of the question although 

 one can frequently determine that there are over twenty. In sev- 

 eral instances, however, in which the positions of the chromo- 

 somes and the degree of the staining were favorable, twenty-two 



distinct chromosomes, never more, were visible. 







There is considerable range in size among the individual chro- 

 mosomes of the spermatogonia as well as observable differences of 

 form. Most of them were rod-like or oval in shape although some 

 were more nearly spherical. In several though by no means all 

 instances two chromosomes, closely associated, were seen lying 

 at some distance away from the main band, out in the cytoplasm. 

 Taking into account this isolation, the rounded shape of these 

 chromosomes and their relative sizes, it seems very probable that 

 they are the two accessory chromosomes which do not manifest 

 their presence for a certainty until the next division. It will be 

 observed that one is somewhat smaller than the other. This con- 

 dition obtains also between the tw r o chromatin nucleoli of subse- 

 quent stages as well as between the accessory chromosomes where- 

 ever they can be identified, and one is led in consequence to 

 strongly suspect that they are all one and the same thing. This 

 inference is all the more justifiable when the relation between the 

 chromatin nucleoli and the accessory chromosomes in some of the 

 lower forms is recalled. 



Fig. 2 represents a nucleus of the primary spcrmatocyte in the 

 spireme stage which shows the two chromatin nucleoli in question. 

 In deeply stained specimens these nucleoli, especially the smaller 

 one, are not always evident but in preparations stained by the iron- 

 hsematoxylin method and then almost entirely decolorized, even 

 as regards the ordinary chromatin of the spireme they are usually 

 conspicuously visible. It should be mentioned that occasionally 

 other small nucleolus-like granules were observable but since there 

 was no constancy in their presence, size or relationship, I h;i\r 



