554 w. W. SWINGLE 



true only of the germ cells of female larvae. The male cells do 

 not undergo the maturation process until several weeks after 

 metamorphosis has occurred, and hence revealed no nuclear 

 changes. 



Mention has been made of the formation of a secondary geni- 

 tal space, and in the explanation of the text figures frequent 

 reference is made to this cavity. A word of explanation might 

 not be inappropriate as the term has been adopted from Kus- 

 chakewitsch. This author explains his use of the term as follows : 



In the development of the germ glands of frog larvae, two kinds 

 of cavities appear — the primary and secondary cavities. The 

 primary spaces are simply those vacant spaces appearing be- 

 tween the germ cells, which have never been obliterated by the 

 migration of the sex cells into the gland and their subsequent 

 multiplication. These primary spaces later become filled with 

 embryonic connective tissue which, later in development, is 

 directly transformed into the definitive connective tissue of the 

 gonad. 



The secondary genital space is the lumen formed within the 

 mass of mesenchyme cells, which proliferate into the gland from 

 the mesonephric region. 



The next series of tadpoles from the control and starved cul- 

 tures was killed May 25, ten days after the date of the last exami- 

 nation. The unfed animals averaged 14.5 mm. in length, show- 

 ing an increase of length of 1.5 mm. in the ten day interval. 

 This slight increase in length was probably due to the fact that, 

 until a few days prior to the date of killing (May 25) the larvae 

 had withstood the deleterious effects of prolonged starvation 

 very well, aside from the fact that growth and development were 

 inhibited. There was little mortality and no disposition on the 

 part of the surviving tadpoles to feed upon their dead compan- 

 ions. About May 22 or 23, however, the mortality among the 

 animals of the unfed culture greatly increased, so much so, in 

 fact, that it became rather difficult to keep the containers free 

 from dead larvae, The surviving animals, if left unmolested, 

 would eagerly feed upon these. Only in this way is it possible to 



