550 



W. W. SWINGLE 



the same. Few yolk spherules were observed in the cytoplasm 

 of the germinal cells of either group (figs. 1 and 2). 



The structure of the germ glands, however, revealed consid- 

 erably more differentiation in the control tadpoles than in the 

 starved larvae. In the controls, the gonads were much larger 

 than those of the unfed animals; the increased size was appar- 

 ently due to a proliferation of the mesodermal cells into the an- 

 lage, together with an increase in the number of germ cells. In 

 the gonads of the control animals, these mesenchyme cells had 



All diagrams drawn to scale with the exception of figure 1. 



Fig. 1 Germ gland of a larva starved twenty-six days from the date of de- 

 velopment of the mouth. Series of May 6. A, primordial germ cell; B, yolk 

 spherule; C, peritoneal cell; D, mesentary transverse section. Oil immersion 

 objective used. 



Fig. 2 Germ gland of control tadpole for animal shown in figure 1. A, germ 

 cell; B, peritoneal cell; C, mesorchium; D, mesenchyme cell; E, primary genital 

 space; F, secondary genital space. X 800. Transverse section. 



migrated into the gland by way of the mesentery and wedged 

 themselves between the germ cells, completely investing some of 

 them in clumps of three or four by delicate cytoplasmic strands, 

 thus forming the germ cell nests which later become the cysts 

 of the ovary and testis. The germ glands of the starved animals 

 presented none of these changes, but instead, remained a simple, 

 grape-like cluster of primordial germ cells, surrounded by a thin 

 investment of peritoneum. No proliferation of mesenchyme' 

 cells into the gland had occurred (cf. figs. 1 and 2). 



