420 
J. BRONTE GATENBY. 
the one in which lies the spindle bridge (PL 23, fig. 4), or 
“ reste fusorial,” which has been formed by a thickening 
of the spindle fibres at the telephase of division (see pp. 435 
and 436). 
In the female the mitochondrial fibres always seem to lie 
quite near, even enveloping the spindle bridge (PI. 24, figs. 
25, 26, and 28), but in the male the mitochondria, even if at 
first they always have this relation with the spindle bridge, 
soon become more granular, and tend to spread around the 
nucleus, as shown in PI. 23, fig. 5. At about this period 
some changes come over the mitochondria ; heretofore they 
resisted the action of acetic acid (PI. 23, fig. 3, is drawn from 
a Flemming fixed cell), and in material fixed with acetic acid 
preservatives these bodies are either hard to see or altogether 
destroyed in later stages (compare figs. 8 and 18). It should 
be understood that up to the beginning of the growth stage 
of the spermatocyte and oocyte the mitochondria of both 
sexes are apparently identical, but after the synizesis stage 
and thence forwards the bodies in either sex behave quite 
differently. The case of the male will be described first. 
After synizesis the chromatin soon becomes arranged, as 
shown in PI. 23, fig. 5, in the manner characteristic of the 
entry upon the growth stage. The mitochondrial cloud, 
which in some cases looks more fibrous than granular, 
gradually thins out, and moves around the nucleus till it 
eventually forms a complete outer sheath to the latter. In 
PI. 23, fig. 6, it is in process of forming this sheath, and in 
fig. 7 the layer is complete. 
As this has been taking place the individual mitochondrial 
granules have been changing. As far as one can ascertain 
from the powers of the microscope at one’s disposal, the mito- 
chondria in the stages drawn in PI. 23, figs. 1, 2, 3, and 4 are 
solid, and from the point of view of staining, homogeneous, 
but from stage PI. 23, fig. 5 and onwards in the male tlie 
character of these grains is altered. Each individual mito- 
chondrial granule has formed within it, or absorbs in some 
way, a chromophobe substance. The mitochondrial matter 
