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BERTRAM G. SMITH 



female, fixed in Bouin's solution, the nucleoli take the nuclear 

 stain very faintly; the vitelline bodies take the cytoplasmic stain. 

 In the most advanced ovocytes of a 30 cm. female (figs. 19 and 

 20) the germinal vesicle is quite centrally situated — a position 

 which it retains until a very late stage of ovogenesis. The nucle- 

 oli, which still stain but faintly, are nearly all at the periphery, 

 where they form a uniform ring. The vitelline bodies shown in 

 the figures now stain brilliantly with borax carmine used after 



20 



Figs. 19 and 20 Sections through ovocytes and ovarian wall of a 30 cm. Crypto- 

 branchus allegheniensis, showing the follicle and the distribution of vitelline bodies 

 and nucleoli. X 00. n., nucleolus; v., vitelline bodies. 



Zenker's fluid; in general they are much more numerous on the 

 side toward the periphery of the ovary, in the region of the future 

 animal pole. Some of the vitelline bodies are very large; these 

 usually occupy an equatorial position, but are sometimes found 

 on the inner side of the ovocyte. Comparison with the preceding 

 stage suggests that the vitelline bodies originate on* the inner 

 side of the ovocyte and migrate to the outer side ; that they reach 

 their greatest development midway in the course of migration, and 

 break up to form the smaller and more numerous vitelline bodies 



