to start a new group of spermatogonia. Between these cells 

 and the spermatocytes there Is always a layer of epithelial 

 cells which persist to form the partitions "between the two 

 successive hatches of seminal elements. The mass of sperma- 

 togonlal nuclei remains small until the spermatids are well 

 advanced In their transformation into sperms. 



As the mass of spermatogonia Increases the developing 

 sperms are crowded more and more to one side of the tuhule. 

 These sperms reach their mature state hefore the second batch 

 enter synapsis. The epithelial cells surrounding the mature 

 sperms, we may suppose, secret a fluid which together with the 

 increasing mass of spermatogonia press the mature sperms out 

 of the tubule. This process is not completed, however, before 

 a third batch is formed or even a fourth started. 



5. Spermatogonial Mitoses . 



In the resting spermatogonia! nucleus the chromatin is 

 arranged in a loose net-work with enlargements at various 

 places tPig. 5). This net, for the most part, lies just in- 

 side the nuclear membrane, the central part of the nucleus 

 containing almost no staining material. The behavior of the 

 chromatin during the prophase of Bltosis is as follows; the 

 knots of chromatin become enlarged and more regular in out- 

 line while the connecting threads become smaller and disap- 

 pear. The chromatin finally assumes the form of a large num- 

 ber of paired spheres (Pig. 6i. An effort was made to count 

 these spheres and numbers were obtained as follows: 61, 55, 

 67, 58, 6E, 62, 68 and 80. One may not however place very 



