2()4 MARSUPIAL QUADRUPEDS OF NEW HOLLAND. 



number of the incisors. The second and fifth divisions of M. 

 Cuvier's arrangement differ only by the presence or absence 

 of a small canine, frequently a mere rudiment, and totally de- 

 void of any assignable influence ; the same remark applies to 

 the third and fourth divisions, the separation of which is real- 

 ly no more, as far as the natural and logical principles of 

 classification are concerned, than a distinction without a dif- 

 ference ; nor is there any valid reason for separating the opos- 

 sums from the other Pedimana, or the Perameles from the 

 kindred saltigrade genera. 



The radical defect of this system, in a scientific or zoologi- 

 cal point of view, and it is an error which systematists con- 

 stantly fall into, arises from attaching an undue value to slight 

 modifications of dentition, without attending to the more im- 

 portant modifications of other organs not less influential ; and 

 often without even regarding the relations which necessarily 

 subsist between organic modifications and the habits and eco- 

 nomy of animal life. It is less troublesome, and perhaps more 

 gratifying to the vanity of our intellectual powers, to infer 

 the habits and appetites of animals from their structure, than 

 to undertake the painful and laborious drudgery of observing 

 them ourselves, or searching for them among the voluminous 

 writings of foreign travellers and historians ; yet this latter 

 process, however tedious and difficult, is the only mode of 

 investigation which deserves the name, or accords with the 

 principles of inductive philosophy, or by which Zoology can 

 eventually pretend to a really scientific character : the other, 

 or a priori process, is but the spurious and vainglorious phi- 

 losophy of the schools, which, ever since the days of Bacon, 

 has been banished from every department of science except 

 Natural History. He entertains a very erroneous idea of the 

 science, who fancies himself a zoologist, because perchance 

 he may be acquainted with the outward forms of animals, and 

 able to refer any given specimen to its proper genus and spe- 

 cies ; he is not less mistaken who conceives himself to be a 

 philosopher, because he has studied their internal structure, 

 and the modifications of their different organic systems ; these, 

 no doubt, are most important facts, but they are only facts ; 

 they are, in conjunction with the observed habits and econo- 

 my of animals, the phenomena or raw material with which 

 the scientific zoologist has to work ; and the relations which 

 subsist between the observed phenomena of structure and 

 economy, is the only true and genuine philosophy of Zoology; 

 which, like all philosophy, is the knowledge, not of simple 

 facts, but of abstract relations. It is only when a distinct, 

 palpable, and necessary relation subsists between structure 



