112 FAMILY CHARACTERISTICS. 



It has been a very simple matter to establish such 

 groups according to the superficial method that 

 has been pursued, for the fact that they are de- 

 termined by external outline renders the recogni- 

 tion of them easy and in many instances almost 

 instinctive ; but it is very difficult to characterize 

 them, or, in other words, to trace the connection 

 between form and structure. Indeed, many 

 naturalists do not admit that Families are based 

 upon form ; and it was in trying to account for 

 the facility with which they detect these groups, 

 while they find it so difficult to characterize 

 them, that I perceived them to be always associat- 

 ed with peculiarities of form. Naturalists have 

 established Families simply by bringing together 

 a number of animals resembling each other more 

 or less closely, and, taking usually the name of 

 the Genus to which the best known among them 

 belongs, they have given it a patronymic termi- 

 nation to designate the Family, and allowed the 

 matter to rest there, sometimes without even at- 

 tempting any description corresponding to those 

 by which Genus and Species are commonly de- 

 fined. 



For instance, from Canis, the Dog, Canidce has 

 been formed, to designate the whole Family of 

 Dogs, Wolves, Foxes, etc. Nothing can be more 

 superficial than such a mode of classification ; 

 and if these groups actually exist in Nature, they 



