24 



genus, he would be startled to find, in the course of his researches, 

 two so called species, in which there was no structural distinction ; 

 and would judge them to be misplaced. So would an observer of 

 the feline tribes, on finding the anatomy of various species to 

 shew very trifling differences, be surprised to detect in two of 

 them, a wide dissimilarity. I believe no instance of this has 

 occurred : if it ever should, the supposed species would probably 

 be removed from the genus to which it had hitherto been 

 supposed to have belonged ; and if not referable to any other, 

 would either form a separate and now genus, or hold the isolated 

 position of an anomalite. 



I must therefore conclude, that where there is a very marked 

 difference, between any two species, a similar marked difference 

 will extend through every species of the genus ; that where the 

 difference is trifling between any two, such trifling diff"erence will 

 characterize the whole ; and that there are no classes, which will 

 not come under one or other of these rules. 





FBIHTED BT WILbUK PBILUF^ HIOH lOWV, BXaBrOBS. 



