164 Helen Dean King. 
could not be ascertained even after metamorphosis was completed. 
These individuals, Hertwig believes, correspond to the ‘hermaphro- 
ditic’”’ forms described by Pfluger. Schmitt-Marcel, ’08, has recently 
studied the structure of the sex-glands in young Rana temporaria 
that appeared to be hermaphrodites. He states that in all cases the 
sex-glands of such individuals, which he calls “intermediate forms,” 
appear much more like ovaries than like testes, yet they probably all 
ultimately develop into testes. In accounting for the origin of such 
forms Schmitt-Marcel assumes that they are derived from young 
females, and he concludes: “Die Veranderung also, die von einer 
normalen weiblichen Driise zu dieser Bildung fiihrt, besteht im 
wesentlichen wohl darin dass bei einem Wachstum des Organes nicht 
in der ganzen Keimdriise ein Heranwachsen von Urkeimzellen zu 
jungen Eizellen stattfindet, sondern dass ganze Strecken auf dem 
Stadium der Urkeimzellen stehen bleiben und sich als solche weiter 
vermehren, wihrend gleichzeitig eine ausserordentliche in der nor- 
malen weiblichen Keimdriise fehlende Vermehrung der Stroma 
Platz greift.” The young ova grow to a considerable size and then 
degenerate ; meanwhile indifferent germ-cell tissue spreads through- 
out the whole sex-gland and later develops into spermatogonia so 
that the individual eventually becomes a male. Schmitt-Marcel 
states that he finds an increasing number of such forms among young 
frogs killed from the second to the tenth month after metamorphosis, 
and that the number of these forms gradually decreases after this 
time. Among adult frogs such “intermediate forms” are not known, 
males and females being found in about equal proportions. 
There is a great similarity between the sex-glands of the “inter- 
mediate forms” found among young Rana temporaria and those of 
young toads having the anomalies described above. In both cases 
large cells, having the general appearance of young ova, are found 
among primordial germ-cells which are still in an apparently indif- 
ferent state. These cells develop to a certain size and then undergo 
processes of degeneration and absorption, leaving the gland male 
or female as the case may be. The chief differences between such 
anomalies in Rana and those in Bufo consist in the fact that the 
large cells which appear in the sex-glands of young toads are, as a 
