V 



PLATE LXV. 



Figs. 1 to 10, inclusive. — Polar views of the equatorial plate from 

 spermatogonia! cells, each showing the entire number of chromosomes. 

 In figs. 1, 2 and 4 the possible pairing of equal elements is shown. There 

 are ten pairs. Nos. 1-1 are the largest two spermatogonia! chromo- 

 somes, which form the largest chromosome of the speimatocyte group. 

 No. 11 is unpaired, and is the accessory chromosome. In figs. 5 to 10, in- 

 clusive, the connecting bands of linin are not shown. 



Fig. 11. — Lateral view of the spindle in metaphase from a young 

 spermatogonia! cyst. 



Fig. 12. — Same from an older spermatogonia! cyst. 



Fig. 13. — Beginning anaphase from an older spermatogonia! cyst, 

 showing the usual confluent condition of the chromatin. 



Fig. 14. — Late spermatogonia! anaphase. 



Fig. 15. — A section of an entire spermatogonia! cyst, showing the cells 

 in different stages of division. The polarity shown is typical. 



Fig. 16. — Early spermatogonia! telophase. 



Fig. 17. — Polar view of the same, in which all twenty-one members of 

 the complex can be distinguished, (x) Accessory chromosome. 



Fig. 18. — Late telophase, from a young spermatogonia! cyst. 



Figs. 19 and 20. — Nuclei of spermatogonia! cells, showing the chro- 

 matin at the point of greatest diffusion. The reticular structure is still 

 evident. 



Fig. 21. — A typical spermatogonia! nucleus, showing the beginnings of 

 the reorganization of the nuclear chromatin. 



Figs. 22 to 28, inclusive. — Successive stages in the re-formation of the 

 spermatogonia! chromosomes. 



Figs. 29 to 33, inclusive. — Nuclei in the process of synizesis. (x) Ac- 

 cessory chromosome, (t) Nuclear membrane, (c) Chromatin mass. 



