WILCOX : SPERMATOGENESIS. 7 
Figures 57-59 as two bodies, one of which is outside the nucleus, and 
in Figures 50, 61, as two bodies, both outside the nucleus — seem to 
me to give evidence of being stages in the history of one and the same 
body. My reason for thinking that they are genetically connected is 
their similarity in size, structure, and reaction to stains. 
During the stages shown in Figures 49, 51, 52, there appears to be a 
chemical change in the constitution of the chromosomes. By the 
safranin and victoria-green method the chromosomes stain red, though 
not so deeply as the nucleoli. At later stages the chromosomes assume 
a green color, while the nucleoli continue to stain red. In still later 
stages (as Figs. 50, 60, 61) the chromosomes again take the red. 
The metamorphosis of the spermatid could be worked out in consider- 
able detail. The chromatin is first arranged around the periphery of 
the nucleus (Plate I. Figs. 24, 27-30). The individual chromosomes 
fuse into a thin shell of chromatin, surrounding, in part, the nuclear 
space. This chromatic shell does not extend over the whole periphery 
of the nucleus, and yet it is so extensive at the beginning of the meta- 
morphosis that in certain views of the nucleus it has the appearance of 
a complete sphere. 
Figures 15-18 and 24—45 show various stages in the spermatid meta- 
morphosis, Figures 62-77 (Plate 11.) present a series of the changes 
which take place in the head of the spermatid. The stage in which the 
chromatin (Figs. 66-72) has the form of a crescent is very common, and 
therefore undoubtedly of considerable duration. 
The origin of the extranuclear body (Nebenkórper), which is stained 
dark green in Figures 20, 27-30, could not be determined. On the an- 
terior end of the nearly mature spermatozoón (Fig. le) is to be seen a 
highly refractive curved tip. Just behind it is a small darkly stained 
body. The body so conspicuous in the neck of the spermatid of Calop- 
tenus (Plate V. Figs, 196-200) was very rarely seen in the Cicada, 
probably because the methods used on Cicada would not stain it. 
Degenerating cells are very frequent in the testicular follicles of Cicada. 
So far as my work on Cicada and Caloptenus goes, amitotic division and 
degeneration affect only the spermatogonia, i. e. if the reproductive cell 
reaches the spermatocyte stage, it completes its course. The first sign 
by which I was able to recognize that a spermatogonium is becoming 
abnormal is due to a chemical change in the nucleus. The chromosomes 
stain more brightly than in normal cells. .The cytoplasm becomes 
clearer and more homogeneous. Then the chromosomes become irreg- 
ular in shape, lose their individuality and fuse into a single mass, as in 
