532 The American Naturalist. [June, 
been developed out of dioecious ancestors, endeavors to prove, 
that hermaphroditism here has been superimposed on the 
female sex alone. He bases his assumption on the fact, that 
in certain normally hermaphroditic Gastropods (Cymbuliopsis, 
Clio striata, Helix aspera, Agriolimax levis, Arion intermedius) 
whenever an individual is found which is not hermaphroditic, 
it possesses the female organs only. But Agriolimax levis is 
certainly, and Helix and Arion probably, proterogynic, so that 
the individuals found with female organs only, should simply 
be considered as individuals in the early stage before male 
organs have appeared. Clio striata on the contrary, and prob- 
ably Cymbuliopsis, are protandric, accordingly the annotated 
female individuals of these two species should be regarded, as 
being individuals which have passed through both the early 
male and the hermaphroditic stage, and through the loss of 
all male elements had become entirely female. Thus Pelse- 
neer’s five cited cases are to be explained as being individuals 
in certain stages of ontogenetic sexual development, and are not 
to be referred to Atavism. To summarize, I agree with this 
zoologist that Hermaphroditism has been evolved out of the 
female state in all proterogynic forms, but in opposition to his 
views, hold that in the case of protandric forms Hermaphrodi- 
tism has been superimposed on the male sex. 
As to those forms, in which so-called “ complemental males” 
are present (e. g. the Cirripedea, and, perhaps, Myzostoma), I 
think that these too may come under either the conception of 
Protandric or of Proterogynic Hermaphrodites. The com- 
plimental males could then, in the case of Protandry, be re- 
garded as individuals which had not yet become hermaphro- 
ditic; and in the case of Proterogyny, as individuals which 
had passed through the ontogenetic female and hermaphroditic 
stages, and had become entirely male. It is perhaps more 
probable that Protandry and not Proterogyny has been the 
method of development in the Cirripedes. However, until our 
knowledge of ontogeny of the Cirripedes has advanced much 
further than its present state, the suggestions here advanced to 
account for the existence of complemental males can ee Be be 
regarded in the light of a hypothesis. 
