GERM GLANDS AND GERM CELLS OF FROG LARVAE 559 



Figure 12 shows three oocytes from ovary of a young frog 

 shortly after completing metamorphosis. Figure 13 is a dia- 

 gram of three follicles from the testis of a young frog three 

 weeks after metamorphosis. 



July 8, one month after the last series of starved larvae of 

 June 7 were killed, another series of unfed tadpoles was pre- 

 served for microscopic examination. The animals had been fed 

 a few hits of algae three of four days previous to the date of 

 killing. The animals were so weak and sluggish when examined 

 that it was considered best to feed them bits of algae rather than 

 risk their dying before the work was completed. At the time of 

 death, the larvae averaged but 16 mm. in length and revealed no 

 signs whatever of limb buds, whereas the controls for this series 

 had completely metamorphosed by June 22, seventeen days 

 previous. 



The germ cells of this series of starved larvae were, for the most 

 part, still of the primitive, sexually undifferentiated type (fig. 

 10). In one or two of the larvae, however, the germ cells ap- 

 peared to be entering the early maturation stages. The chro- 

 matin had arranged itself into the thin spireme threads charac- 

 teristic of presynaptic stages. The total number of germ cells 

 within the anlage appeared to have increased somewhat as com- 

 pared with the number observed in the germ glands of the unfed 

 animals killed at earlier dates. 



The germ glands of this unfed series of tadpoles were unde- 

 veloped, although the number of mesenchyme cells within the 

 gland had increased somewhat when compared with the glands 

 of previous series. Correlated with this increase in the number 

 of mesenchyme and germinal cells, there was an increase in the 



Fig. 8 ( term gland of cont rol for animal shown in figure 7. Scries of .June 7. 

 I. mesorchium; B, primary genital space: C, germ cells in synizesis; l>, ovarian 

 cysts. X 800. Transverse section. 



Fig. !) Germ gland of control larva from series of June 7. .1, germ cells in 

 synizesis; !>. embryonic connective tissue. X SOD. Transverse section. 



Fig. 10 Germ gland of larva starved ninety-seven days. Series of July 8. 

 .1 . mesenchyme cell; />'. mesorchium ; (', germ cells, x 800. 



Fig. 11 Germ glands of larva starved ninety-seven days. Series of July 8. 

 .1. germ cells in pre-synaptic stages. X son. Transverse section. 



