227 
Later (car. 50 mm), they may still be found in the peritoneum after the 
seminiferous tubules have broken away from it; but they are no longer 
found in the stage of car. 73mm. No doubt they all degenerate, since 
it is out of the question for them to migrate through the thick albu- 
ginea. LAULANIE (’86), who observed similar phenomena in the chick, 
held that the persistence of the sex-cells in the peritoneum pointed to 
a hermaphroditic condition quickly passed over in development. It 
would seem more plausible, however, to consider them as identical 
with the spermatogonia, left behind by chance, as it were, in the de- 
Ovary 
Fig. 7, Fig. 8. 
Figs. 7 and 8. Camera lucida diagrams of transverse sections of sex-glands from 
embryos of 19 mm total, 11,5 mm car. length. X 124. 
Fig. 9. A portion of the cortex of an ovary from an embryo of 15 mm ear. 
length. X 721. 
i Fig. 10. A portion of the cortex of an ovary from an embryo of 27 mm ear. 
length. X 721. Sex-cells are easily distinguishable from peritoneal cells. Four 
oöcytes appear in the upper part of the figure and four oögonia in the lower part. 
velopment of the sex-cords. They should be considered in the same 
light as the sex-cells which originally failed to find their way into the 
sex-gland anlagen. 
A study of numerous stages in the development of the testis shows 
the seminiferous tubules to be composed of two types of cells — 
15% 
