778 THOS. H. MONTGOMERY, JR. 
separated from both of these bodies. Thus the mitochondria 
become scattered throughout the cell body but most abundantly 
in a perinuclear zone, as shown in figs. 42-55, 57-59, 61-63, 65, 
66, 71, 84,85. So far as could be determined they are unbranched 
threads, though often twisted and angularly bent. What their 
number is was not ascertained, the drawings representing with 
fidelity only the majority of those present in a particular plane of 
some thickness and only those seen with the greatest distinctness. 
Thus they come to make a thick mesh. In general they are bent 
around the nucleus, and mitochondria that appear on the drawings 
to terminate against the nuclear membrane do not really end so 
but curve around its surface. When the centrioles become visible 
the mitochondria in their vicinity frequently converge towards 
them (figs. 57-59, 61-63, 65, 66, 71, 84, 85). Very often they 
are so closely looped upon themselves that the enclosure of such 
a loop may present the appearance of a granule with a sharp bor- 
dering line, and this illusion is the more striking in the cases 
where the mitochondria are faintly stained; such appearances 
misled me in 1898 into supposing the mitochondria to be a mass 
of large granules. But when they are deeply stained it can be 
determined that there are no large granules in the cytoplasm 
except the chromatoid corpuscles. 
During the prophases of the maturation divisions they become, 
for the most part, smooth, continuous threads, though some 
may retain the earlier appearance of chains of granules. Each 
thread is not always of even thickness throughout but frequently 
is irregularly dilated, as I have shown in the drawings. 
I have looked to see whether there occurs in the mitochondria 
any process analogous to the process of pairing of the chromo- 
somes, but have found no evidence of it. 
The stages just described were worked out mainly upon one 
preparation, for the reason that this was most excellent for the 
examination of the sphere. The stages next to be described have 
been drawn from the sixth follicle of testis no. 265 which exhibited 
more clearly than any other the mitochondria during the matura- 
tion mitoses. In this testis they also appeared uniformly of 
