568 
J. BRONTE GATENBY. 
of spermatogonia. This process takes place from different 
parts of the alveolar wall and the lumen becomes quite choked 
with cells. In Text-fig. 2 is drawn a lower part of the 
alveolus showing that the proliferation of male cells from the 
walls has stopped temporarily and that the yolk cells are 
much reduced in size. 
The consecutive stages from spermatogonium to spermato- 
cyte are marked with figures. Quite often one finds oocytes 
developing beneath the yolk cells. In such a case as the 
group of spermatogonia marked i, in Text-fig. 2, many of the 
cells may go on to the growth period and ultimately form 
spermatozoa, but there is hardly any doubt that some remain 
quiescent, or keep on dividing and give rise to the very small 
spermatogonia with hardly any cytoplasm which are so 
characteristic of the lower part of the ovotestis lumen. In 
Text-fig. 3 another stage is reached. The yolk cells are- 
either relatively few or small, or often not present at all, but 
the lumen is generally strewn with a mass formed of the flot- 
sam and jetsam of many generations of germ-cells of ripe 
spermatozoa, of exhausted yolk cells or their nuclei, and of 
many sizes of spermatogonia; also here and there around 
the walls may be seen either an oocyte in process of growth, 
often but not always accompanied by yolk cells, or a bunch of 
spermatocytes, spermatids, or spermatozoa. If such a stage 
as the contraction figure be taken, one is struck by the fact 
that many sizes of cells are undergoing this nuclear change,, 
often with a cytoplasm and nucleus varying remarkably in 
size. In Text-fig. 2 there is no doubt that all the cells are of 
Text-fig. 2. 
Fig. i. — Slightly lower region than that drawn in Text-fig. 1, ii. All 
cells belong to the same generation. Earliest stage at 1 has just 
finished division. 2-7 are growth stages. 8 = spermatid. The 
yolk cells ( N.C .) are beginning to become exhausted. The Neben- 
kern rods of this generation were semi-lunar in shape. Fig. ii. — 
Further down the diverticulum, where the yolk cells are more 
exhausted or absent. The epithelium at the figures 1-5 is beginning 
to produce another generation of male cells. 5 is about to enter 
the prophases of mitosis. 7 = spermatocyte, 8 = spermatid. The 
cell 2 is drawn in PI. 31, fig. 17. 
