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stages, but at sexual maturity as well. I can not at present offer an 
opinion as to their significance. 
Immediately after emergence from the egg (car. 25 mm), a large 
number: of oögonia begin to enter the typical oöcyte stage of synapsis. 
In later stages (car. 27” mm), many oöcytes have passed synapsis and 
some few are found to have greatly enlarged. These are provided 
with a layer of follicle cells. 
Munson (’04) states that in the tortoise Clemmys, each single 
oögonium gives rise by subdivision to eight daughter oögonia, the 
central one of which enlarges to form an oöcyte, while the sister cells 
become its granulosa cells. I have found nothing of the sort in Chry- 
semus. There are, it is true, nests of oögonia, but these develop into 
oöcytes, passing simultaneously through the unmistakable stage .of syn- 
apsis. Only later do these nests break up and peritoneal derivatives — 
granulosa cells find their way into their midst. It frequently happens 
that odgonial nuclei may divide many times without an accompanying 
division of the cytoplasmic mass in which they lie. In many such 
cases, all of the nuclei but one suffer degeneration. This process has 
not been studied in detail, but many cases have been found in which 
the results and at least certain stages of the process are clearly evident. 
The nuclei decrease greatly in size and react but slightly to the staining 
reagents. Examination of all stages in the formation of follicles shows 
that the granulosa cells are derived from the peritoneal cells and from 
them alone. Thus we find a strict dualism in the formation of the 
ovarian tissues, which is sharply defined from the period when the 
egg is laid or earlier, up to the period when well marked ovarian 
follicles are distinguishable. Later stages, concluding with one shortly 
before sexual maturity (car. 85 mm), were studied and served to merely 
bear out these conclusions. 
Figs. 7 and 8 show the early differences between ovary and testis. 
In the former, the sex-cords are far more slender than in the latter 
and are attached to the peritoneum by much broader bases. While 
in the ovary the oögonia are more numerous in the peritoneum than 
in the sex-cords, the reverse is true of the spermatogonia in the case 
of the testis. While the sex-cords of the ovary break away from the 
peritoneum at an early period, those of the testis remain attached 
until after the time of hatching (car. 25 mm). 
Numerous primary sex-cells remain in the peritoneum and never 
find their way into the seminiferous tubules. In the earlier stages 
after sex differentiation, they are usually grouped in those parts of 
the peritoneum to which the seminiferous tubules are still attached. 
