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J. BRONTE OATEN BY. 
appears to me that such peculiarities are due to the effect of 
the fixative on the matter around which the true mito- 
chondrial substance is applied ; thus the filamentous condition, 
of which PI. 25, fig. 31 is an example, is probably due to the 
rupture of the outer layer by the “brutality ” of the fixative 
and the consequent running together of the rims of the mito- 
chondria. This last process is one which the mitochondrial 
bodies always have a tendency to undergo. It may, then, be 
stated that the running together, though a natural process in 
later stages, is artificially hastened by the action of the 
fixative. In my sections of Smerinthus populi, the cells 
nearest to the periphery have a more vacuolated mitochon- 
drial mass than the cells which are in the mid-region of the 
gonad, and to which the fixing fluid (Champy) must have 
taken longer to penetrate. 
The Mitochondria in Division of Spermatocytes. 
In PI. 23, figs. 9, 10, and 11, PI. 24, fig. 27, and in PI. 25, 
figs. 32, 33, and 34 are drawn stages in division. 
These stages seem to show that the ainphiastral rays may 
be partly concerned in the division of the mitochondria 
between the two daughter cells. These bodies generally 
keep clear of and rarely become completely tangled in the 
spindle fibres. The mitochondria near the poles of the 
spindle in PL 23, fig. 9, are unusually near to the centro- 
sotnes, but there is a clear space left around the latter. This 
spermatocyte was drawn from material preserved in Champy, 
and the astral rays stain very slightly. The mitochondria 
generally become grouped to one side of the cell as in 
PI. 23, fig. 9, but this is not the only state in which they are 
found. Very often they form a complete circle, as shown in 
an equatorial view in PI. 23, fig. 11, and PI. 25, fig. 33. It is 
during division that it becomes very obvious that the indi- 
vidual mitochondrial bodies are affected by what is taking- 
place in the cell ; some mitochondrial bodies become elongated 
in the longitudinal axis of the spindle, others run together 
