GERM CELLS OF HERMAPHRODITES 207 
or spermatozoa as a result of various causes, some 
general and others local in nature, which probably 
are most influential at certain definite stages in the 
cellular activity. A new equilibrium is thereby es- 
tablished between the different cell organs which 
initiates new processes resulting in differentiation. 
The undifferentiated cells in the testis of the adult 
appear also to be identical with the primitive sper- 
matogonia, and have still the power of producing 
either ova or spermatozoa. Thus the male amphib- 
ians are also females “en puissance,” but the re- 
verse is not true. This accounts for the numerous 
discoveries of ova in the testes of these animals. 
Reports of so-called hermaphroditism in amphib- 
ians are abundant in the literature. Cases have 
been reported in frogs by Cole (1895), Friedmann 
(1898), Gerhartz (1905), Ognew (1906), Yung 
(1907), Schmidt-Marcel (1908), Youngman (1910), 
Hooker (1912), and many others. Hooker has re- 
viewed the literature of the subject. Hermaphrodit- 
ism in other amphibians is more rare, but it has 
been noted in salamanders by La Vallett St. George 
(1895) and Feistmantel (1902). Usually the condi- 
tion spoken of as hermaphroditism consists in the 
presence of ova in the testis, and it is probable that 
true hermaphroditism is rare in these animals as it 
is in other vertebrates. In the toad, however, a 
condition exists which is of particular interest. The 
genital ridge of every toad tadpole 15 to 18 days old 
becomes visibly differentiated into two regions, an an- 
terior portion which develops into Bidder’s Organ, and 
