MUNSON: SPERMATOGENESIS OF PAPILIO. 
69 
and consequently vertical to the body of the grandmother cell (pi. 12, 
fig. 4). 
13. Division of the branch cell, consequently, results in two 
unequal daughter cells, a proximal attached portion (pi. 15, fig. 57a, 
i.), and a distal free spherical cell, the primary spermatogone (pi. 
15, fig. 57, p. g.). 
.14. The cortical nuclei not only surround the protoplasmic strands 
or branches, but extend also around the branch cell, the one at the 
distal end becoming especially developed (pi. 15, fig. 57, c.). 
15. When the branch cell divides, some of the mantle nuclei 
including the large distal nucleus (c.) are pinched off with the primary 
spermatogone. 
16. The nuclei thus associated with the primary spermatogone 
become the cyst cells (pi. 15, fig. 57b). 
17. The proximal attached sister cell grows after division to the 
normal size of the mother branch cells and then divides again. 
18. Chains of three or four spherical primary spermatogones can 
thus be seen directly in line with each mother branch cell, having 
been pinched off from it, as it were, like so many buds, but by a process 
of karyokinesis (pi. 12, fig. 4). 
19. Beyond these chains of primary spermatogones may be seen 
isolated spindles, the first division of the spermatogone into a two- 
celled gonocyst. 
20. It is only in this vicinity that 1 have ever found isolated divid¬ 
ing cells and gonocysts in the two-celled or four-celled stage (pi. 12, 
fig. 4, c, d, e). 
21. In the advanced gonocysts, all cells divide at the same time 
(pi. 13, figs. 30, 31). Hence single spindles cannot be seen, except 
where primary spermatogones begin their first division (pi. 12, fig. 
4, b). 
22. Soon after the primary spermatogone divides, the cortical 
nucleus accompanying it may also be seen to divide mitotically (pi. 
12, fig. 4, /). 
23. The spindle of the primary spermatogone does not have that 
constant position which the mother branch spindle has with reference 
to the grandmother stem cell (pi. 12, fig. 4, b). 
24. Beginning with the grandmother stem cell as a center and 
drawing a line radially outward as in plate 12, figure 4, there are, first , 
the mother branch cell; second, one or more primary spermatogones; 
