264 WILBUR WILLIS SWINGLE 
appears as though there had occurred a running together of the 
chromosomes. The lugs or knobs marking the synaptic ends of 
the chromosomes round off and disappear, leaving an oval-shaped 
shiny mass, resembling a heavily stained oil drop. Such masses 
tend to run together, forming larger units, until in final stages 
of the process the original fourteen tetrads are represented by 
three or four large deeply staining spherical masses (fig. 22 and 
23). During this time the nuclear wall may or may not have 
disappeared, depending upon the age of the spermatocyte when 
degeneration began. Where this process sets in after spindle 
formation there is no nuclear wall. In cases where the nuclear 
membrane is present, the entire nucleus is excentric in position 
(fig. 106). In those cases where degeneration begins after the 
complete formation of the mitotic figures, and after the tetrads 
are arranged on it, the history of the degeneration is slightly dif- 
ferent from that just described. The essential difference is that 
there is no nuclear wall present, the spindle apparatus is resorbed 
into the surrounding cytoplasm, and the tetrads go to pieces in 
situ. The latter take on the appearance of oily masses which may 
or may not fuse together. In final stages, all that remains of 
the fourteen tetrads and mitotic figure is a group of oily vacuoles 
grouped together much in the same fashion as the chromosomes 
were grouped on the spindle. In many instances the number, 
and even the size relations of the vacuoles corresponds to the first- 
maturation chromosomes (figs. 109 and 110). 
The cytoplasmic changes accompanying these regressive 
nuclear p^enomena are interesting. The normal, clear, lightly 
staining protoplasm becomes yellow in color, much vacuolated, 
and numerous spherical droplets of yolk-like substance appear. 
In this connection it is interesting to note that an essentially 
similar yolk-like material has been described and figured by prac- 
tically all workers on apyrene spermatozoa. For instance, 
Gould's ('18) description and figures for Crepidula plana and 
Reinke's ('12) figures of Strombus. However, as the substance 
in question occurs in degenerate and functionless cells in all 
cases, the presence of similar degeneration by-products is to be 
expected and has no special significance. The writer doubts if 
this substance is yolk, though it does resemble it. 
