776 THOS. H. MONTGOMERY, JR. 
to one side of the centriole, while at the opposite edge of the cen- 
triole the axial thread is rooted (figs. 127-134). By reason 
of the inclusion of two vacuoles of different sizes the sphere comes 
to show a bilobar form with an annular constriction, and just 
after the occurrence of the nuclear discharge it divides into two 
(figs. 185, 1386). The posterior portion (Sp.) becomes still paler 
and wanders into the tail of the sperm (figs. 185-139), often pass- 
ing a considerable distance behind the head (a greater distance 
than shown in any of the figures) ; there it becomes more and more 
indistinct, but I do not know whether it disappears entirely. 
The anterior portion of the sphere (Pf, fig. 135) suddenly becomes 
deep staining at the time of its separation from the posterior 
part, perhaps by addition to it of some of the material discharged 
from the nucleus. It separates completely from the posterior 
portion (fig. 136, Pf), then passes forward along the nuclear sur- 
face (fig. 137) until it arrives at the anterior end of the nucleus 
(figs. 138, 1389). There it becomes gradually elongated (figs. 
140-144, 146) and thus comes to compose the lance or perfora- 
torium of the mature sperm (fig. 147). The mature lance is 
frequently thread-like and branched, nearly pseudopodial, and 
penetrates into the cytoplasm of the follicular nurse cells. I could 
not determine whether there is a cytoplasmic envelope around it 
and the nucleus of the mature sperm. 
This sphere of the spermatid resembles that of the spermato- 
cyte in optical appearance and in having no connection with 
centrioles; but differs in its elaboration of vacuoles, in its changes 
of form, in its division, and especially in having a close contact 
relation with the nucleus. The evidence is that these two spheres 
are dissimilar structures. 
D. The mitochondria 
These bodies had been figured in my paper of 1898 and described 
for the growth period of the spermatocytes, under the name of the 
idiozome mass. But I did not distinguish them from the idio- 
zome and sphere, nor did I possess suitably stained slides for their 
