AND THE LOWEE ANIMALS. 127 



the precise reason that the phenomena we considered 

 before, become here more strange and complex than 

 ever. I shall, however, attempt the task, which 

 without the assistance of illustrative figures is by no 

 means an easy one. 



In the first place, we shall mention the simplest 

 facts bearing upon the subject, and those also which 

 were first observed. 



In all the animals previously spoken of, a new 

 generation can be produced only through the inter- 

 course of two individuals of opposite sexes. This 

 fact is so well known that it has been always regarded 

 by the mass as one of the great laws of Nature. The 

 exceptional facts observed in the case of man himself, 

 and perhaps also the fables of the ancients, prepared 

 naturalists for the discovery of certain animals in 

 which the attributes of both sexes were united in a 

 single individual. The idea of hermaphroditism, 

 which they had readily accepted, was at last proved 

 correct, and exemplified among some of the inferior 

 animals by which we are surrounded,— the earth- 

 worms and slugs for example. 



These discoveries, extended at a later period by 

 Adanson's beautiful researches upon mollusks,^ gave 

 a new interest to the very difficult problem — Can 

 any animal be a male and female parent, in the entire 

 acceptation of the word, without having intercourse 

 with another individual ? 



A great many naturalists, led by reason only, re- 

 plied in the affirmative ; but the direct observation of 

 animals placed apparently under the most favourable 



* " Histoire Naturelle du Senegal," 1759. 



