574 
J. BRONTE OxATENBY. 
to be the front end of the cell, the nucleus is found to be 
covered at one side by a densely staining cap — the acroblast. 
Despite especial work in this connection, I have been unable 
to follow this body back into the spermatocyte. No staining 
method of which I know will discriminate between acroblast 
and mitochondrium, and it is obviously impossible to identify 
this body until it has taken up its position next to the front 
edge of the nuclear membrane. The spermatid, 1 besides con- 
taining the Nebenkern and the mitochondria, is seen to be 
provided with a cloud of granules of a smaller size lying 
behind the nucleus, near the locality from which the axial 
filament presently begins to grow. The granules (AT. 2 ) are 
hardly demonstrable till the spermatid is in the stage drawn 
in PL 33, fig. 35, but from thence onwards they are quite 
easily found. 
As the spermatid lengthens, the nucleus becomes shaped as 
shown in PI. 34 , fig. 41, the acroblast lying as a thickened 
area laterally. In PL 33, fig. 36, I have carefully drawn a 
spermatid at this stage. The nucleus has become blackly 
stained with iron hsematoxylin, while the small granules, 
which will be’ called micromitochondria, are closely grouped 
behind the nucleus. The other mitochondria, which, to dis- 
tinguish them, will be called the macromitochondria, lie 
further back. At the letter C . 2 is a structure, constantly 
present, formed of a large and a slightly smaller granule. 
The larger granule is probably the second centrosome ; the 
other might be a mitochondrial granule, but I cannot advance 
any definite evidence as to its nature. A stage just before 
this is drawn in PL 34, fig. 42, and the nucleus does not yet 
stain entirely basophil. In PL 34, fig. 43, a still later stage 
is drawn. The micromitochondria ( M . 2 ) are now grouped 
around the axial filament a good part of its way, and the 
centrosomic structure is still visible. 
In Text-fig. 4 iii a later stage is drawn ; in this (preparation 
the two bead-like bodies in the tail of the sperm were par- 
ticularly obvious. 
1 See Addendum A. 
