225 
found, although in constantly decreasing number and size. This re- 
duction of the yolk of the repeatedly dividing sex-cells may result 
from their increasing need of nourishment. 
During the growth of the indifferent sex-gland, the sex-cells are 
found in the peritoneum and in the sex-cords. In the female, the 
sex-cords become the medullary cords, breaking away from the peri- 
toneum when the carapace has reached a length of 14 mm. Scattered 
sex-cells, whose fate was not determined, are found in them, yet it is 
safe to assume that they suffer degeneration, as in the mammals, be- 
cause the only remnant of the medullary cords found in au almost 
mature ovary (car. 85 mm) consisted of small tubules of epithelial 
cells continuous with the rete ovarii tubules found in the mesovarium. 
The greater part of the sex-cells remain in the peritoneum, which 
now becomes sharply separated from the ovarian stroma by a well de- 
fined layer of connective tissue. They soon begin to divide, causing 
the peritoneum to greatly increase in thickness, until in the turtle of 
car. 27 mm, it becomes as thick as the cylinder of stroma which it 
encloses on three sides. 
The primary sex-cells of the ovary shall hereafter be termed 
oögonis, for such they are beyond a doubt. At no time is there the 
slightest difficulty in distinguishing them from the peritoneal cells. 
The criteria given earlier in the paper still apply. 
Compare Figs. 6, 9, and 10. 
The oögonia in this, and in subsequent stages, 
vary greatly in size. This is undoubtedly due to 
Fig. 6. A portion of the sex-gland anlage of an embryo 
of c-t 6,8 mm length. X 721. The sex-cell lies in the peri- 
toneum. Beneath it are seen two cells of an incipient sex-cord. 
the differing frequency of cell division and the length of time elapsing 
in each case since the last division. Pairs and clusters of cells give 
ample evidence on this point. 
In the stage of car. 27 mm, there first appearss a type of oögo- 
nium characterized by an irregular, often crescentic nucleus. The con- 
Cavity is always filled with the centrosphere, which may, indeed, be 
the cause of the indentation. The chromatin is often situated more 
peripherally than in the normal oögonia. These modifications are 
neither necessarily preliminary to cell division, nor to the assumption 
of the Synapsis stage, because both these processes were observed to 
take place in earlier stages before this type of odgonium appears. 
Spermatogonia similar to these oögonia make their appearance in the 
testis. In both ovary and testis they are found not only in these early 
Anat. Anz. XXIX Aufsätze, 15 
