560 W. W. SWINGLE 



size of the gland, an increase greater than any revealed by other 

 series of starved animals. None of the morphological criteria for 

 sex differentiation were observed in the gonads of this series. 



In the two larvae previously mentioned, i.e., those whose germ 

 cells appeared to be entering the early maturation stages, the 

 glands appeared to be male in character. The early maturation 

 changes, however, are characteristic of female cells, previous to 

 oocyte formation (fig. 11). 



It seems anomalous that the germ cells of two of the unfed 

 larvae should, in regard to development, be so far in advance of 

 the gonad itself; for as was stated, many of the germ cells of 

 two of the animals appeared to be in early maturation stages, 

 whereas the gonads remained a simple cluster of cells. No dif- 

 ferentiation of the gland had occurred. In all of the larvae 

 heretofore examined, differentiation of the germ cells from the 

 primitive, apparently sexually indifferent type, to the matu- 

 ration stage, was correlated with marked development and dif- 

 erentiation of the germ gland anlage; the two conditions were 

 apparently intimately related. 



It may be that the two larvae whose germ cells presented such 

 advanced developmental stages over the other animals of the same 

 age and series, had succeeded in getting more food to eat than 

 the other animals. Aside from a few filaments of algae now and 

 then, however, these animals received nothing to eat. 



It may also be true that starvation inhibits the onset of the 

 maturation processes of the germ cells for a definite time only, 

 beyond which, its effects are not sufficiently potent to overcome 

 the inherent tendencies of the sex cells to undergo differentiation. 



It is unfortunate that more of the larvae of this series were 

 not preserved for microscopic examination. 



I succeeded in keeping three tadpoles of the starved culture 

 until August 29, i.e., one hundred and thirty-nine days from the 



Fig. 12 Oocytes from gonad of young frog of same age as animal shown in 

 figure 11. A, Follicle cell. X 800. 



Fig. 13 Three seminiferous tubules from the testis of a young frog the same 

 age as animal shown in figure 11. A, Interstitium; B, germ cells; in prophase 

 stages of the first maturation division. A few sperm cells were observed. X 800. 



