234 M. I. G. Saint-Hilaire on an American Bat. 



The second question is easily answered ; who, in fact, doubts 

 the importance of characters derived from the country they inha- 

 bit^ in distinguishing species ? How many of our French animals 

 are unknown in the countries nearest to us ? How many are 

 found even only in one single province, to the exclusion of all the 

 rest ? Where we see Nature varying in this manner, almost 

 from field to field, how can we refuse to take into consideration 

 the boundaries marked out by immense oceans ? 



The first question presents a substantial difiiculty ; perhaps we 

 have not, even yet, sufficient data for its solution ; at least, the 

 consideration of a fact so novel, and contrary to received opinions, 

 as that which forms the object of this paper, would induce me 

 to think so. 



Buffon remarks * that the animals of one continent are want- 

 ing in the other, and that this holds good for all, those excepted 

 which breed in the northern climates. He explains the exception 

 by the contiguity of the two continents towards the north. 



This observation, which Buftbn applied only to animals con- 

 sidered in regard to species, may be extended also to genera, at 

 least to those of the first families. Buffon, though he did not so 

 express himself in his writings, doubtless was of that opinion, 

 since he was bold enough, though he knew but a few species of 

 Monkeys cf either continent, to trace characters for the whole, 

 founded on the differences which distinguish the A.merican Mon- 

 keys from those of the old world. The discoveries of Naturalists, 

 since Buffon, have confirmed what he advanced, so that his idea, 

 bold and perhaps even rash originally, may now be considered 

 as the fruit of an admirable perception of the relations of ani- 

 mated beings, and as the work of a genius which outstripped the 

 knowledge of its own day. 



It is very worthy of remark, and perhaps the fact may be ex- 

 plained by the greater attention which Zoologists have paid to 

 the study of the animals most resembling man, and to the con- 

 sequently more careful formation of the first genera ; it is very 

 remarkable, I say, that in proportion as we descend in the scale 

 of beings, the existence of animals common to both worlds be- 

 * Animaux Communs aux deux CotUinens, t. ix. p. 97, et suiv. 



