T 6 J. E. WODSEDALEK. 



the early spermatogonial stages, except that the cells are larger 

 and the linin strands a little more conspicuous. The large 

 nucleolus is again very distinct and appears as it did in the 

 spermatogonia. A large, irregularly shaped karyosome is also 

 usually present, as are a number of small ones. As the cell in- 

 creases in size the linin strands become more conspicuous and the 

 chromatin granules more numerous. The karyosomes, too, 

 become larger and are surrounded by dense masses of chromatin 

 granules. One of the karyosomes is always large and has from 

 eight to twelve linin strands radiating from it. Frequently a 

 few strands can be seen radiating from the small karyosomes. 

 These radiating strands together with many others, form a 

 continuous network of linin. Later the chromatin granules begin 

 to mass around the linin strands and the karyosome begin to 

 disappear (Fig. 7). Soon all of the chromatin material seems to 

 be arranged along the linin strands, which take on the appearance 

 of a network of chromatin threads. The threads are very granu- 

 lar and vary a great deal in length and somewhat in thickness 



(Fig- 7)- 



There is no definite arrangement of these threads in the net- 

 work of the various cells. Each cell seems to have its own hit- 

 and-miss tangle. In some cells the long threads are more nu- 

 merous and the short connecting threads are proportionately 

 fewer in number. In others there are many short components 

 forming the network. The nuclei at this stage vary considerably 

 in size. 



Synizesis, which is so commonly observed in the horse tissue, 

 does not occur in the mule. The nearest approach to it is a 

 small clump of threads which is frequently seen and seems to be 

 formed in the position occupied by the large karyosome. This 

 clump persists in many cells until the threads break up into 

 chromosomes. The mass of chromosomes resulting from such a 

 clump of threads can also be frequently seen. It is probable that 

 the clump of threads is brought about by the tangling up of the 

 linin strands, which extend from the karyosome. 



The spireme stage which follows synizesis and synapsis in the 

 horse is also lacking in the mule. The expanded network takes 

 its place, and only parts of the network resemble the spireme of the 



