SPERMATOGENESIS OF ASCARIS FELIS GOEZE 191 



The examination of 1103 spermatogonia! nuclei which were in 

 the 'resting stage' showed 917 containing two clumps of chromatin, 

 one about ten times as large as the other (fig. 1) . That this smaller 

 body was not a plasmosome was shown by the staining reac- 

 tions, as it responded in every case exactly as did the larger 

 mass of chromatin material. 



The cytoplasm of the early spermatogonia! cells shows a 

 slightly reticulated structure that gradually changes to a granular 

 texture as the spermatogonia become older. By • the time the 

 last spermatogonia! divisions are completed the granules have 

 coalesced, becoming larger and fewer in number and taking a 

 heavy plasma stain. These granules behave in the same manner 

 as they do in A. megalocephala and A. canis (Walton, '16 b) 

 and ultimately form the nutritive yolk cap of the spermatozoon. 



h. Maturation stages 



1. First spermatocytes. The chromatin of the spermatocytes 

 during their growth period appears in the form of two irregular 

 masses situated peripherally in the nucleus, and similar in all 

 respects to the chromatin bodies noted in the spermatogonia! 

 nuclei. The mass of the smaller body is about one-tenth that 

 of the larger. A distinct plasmosome makes its appearance, 

 but gradually disappears at the time of the differentiation of the 

 chromosomes. 



Near the end of the spermatocytic growth period the two 

 chromatin masses become an integral part of a system of peripher- 

 ally placed linin fibers (fig. 2). Soon after becoming a part of 

 this peripheral network, the two chromatin bodies show a 

 segregation of their contained chromatin material into dis- 

 crete bodies embedded in a thick background of linin. The 

 larger of the two centers of chromosome formation gives rise 

 to nine of these small aggregations of chromatin, while the 

 smaller center gives rise to only one aggregation (fig. 3) . These 

 minute chromatin clumps assume the definite form of chro- 

 mosomes as the linin background disappears. The nine chromo- 

 somes are of the tetrad form, while the single chromosome is a 

 diad. 



