156 RAYMOND BINFORD 
between the nucleus and the capsule, with a clear space between 
it and the nucleus. If the spermatid shown in this figure were 
rotated to the right through 90° so as to bring the outer surface’ 
of the wedge of cytoplasm on the side toward the observer, we 
would have the appearance presented in figure 46. If we should 
turn this through 180° so as to throw the wedge on the opposite 
side from the observer, the spermatid would appear as in figure 
47 where just the tips of the crescent shaped wedge are seen. 
The tips of this crescent progress around the capsule along the 
boundary line between the nucleus and the capsule. At the 
same time the thick side of the wedge is reduced and the mate- 
rial is distributed equally around this border-line to form a com- 
plete ring, which viewed from any lateral direction, has the 
appearance shown in figure 48. At first the substance of the 
wedge is finely alveolar in appearance but by the time the ring 
is completed it seems to be uniform throughout and is stained 
black with iron-hematoxylin. It seems to be identical with the 
mitochondrial substance described by Koltzoff (’06). 
After the mitochondrial ring is completed, the nucleus becomes 
widely separated from it and the capsule (figs. 50 to 52). This 
however is not always the case. In two preparations from which 
figures 33 to 35 and 37 to 43 were drawn, the nucleus remained 
fitted closely down on the capsule as shown in figure 43. As 
the two different conditions were obtained with the same fixing 
fluid it is hardly probable that. the difference was caused by the 
fixing. The nucleus at this time loses the last trace of any 
granular or reticular structure and becomes uniform in its stain- 
ing reactions, and somewhat reduced in size. 
About the time the mitochondrial mass begins to slip in between 
the nucleus and the capsule, one or two deeply staining granules 
appear on the border line between the nucleus and the capsule 
(figs. 44 to 48). Koltzoff (06) in his researches on the sperma- 
togenesis in Galathea squamifera, has identified these granules 
with the centrosome. In my preparations of Menippe merce- 
naria I am able to distinguish the centrosome for some time 
after the second maturation division (figs. 28 to 32) but, in the 
later resting period of the spermatid and in the stages during 
