HERMAPHRODITISM. 79 



of each must be taken into account. But where the hermaph- 

 roditism is manifestly exceptional, there can be seldom any 

 question in regarding it as a reversion. The reversion would 

 generally occur on the female side, for on a priori physiological 

 grounds, it is, as Simon remarks, more readily intelligible that 

 a female should produce sperms, than that a male should 

 produce ova. In this connection it is interesting to notice 

 how Brock, in regard to the development of the reproduc- 

 tive organs of snails, maintains that they are laid down and 

 developed on the female type, and only become secondarily 

 hermaphrodite. Purely female forms still occasionally occur, 

 which he interprets as exaggerations of the side normally 

 preponderant. So in hermaphrodite bony fishes, the same 

 author has shown that the preponderance is distinctly female. 



Hermaphroditism is associated in some cases {eg.^ Polyzoa) 

 with the occurrence of parthenogenesis in allied forms ; and it 

 may be noted, as will become clearer afterwards, that for a 

 female to become hermaphrodite is a sort of step towards 

 parthenogenesis. It means that certain cells of the reproduc- 

 tive organs are able to divide of themselves, — to form, however, 

 not an embryo, but a bundle of sperms. 



The general conclusion then is, that hermaphroditism is the 

 primitive condition, and that the cases now existing either 

 indicate persistence or reversion. 



