344 



ON THE MARSUPIAL QUADRUPEDS 



foot in walking, the pace is slow and confined to the surface 

 of the earth, and the toes are so firmly united as to be alto- 

 gether destitute of separate motion. The dentition, as far as 

 regards the number of incisors, may be called rodent, though 

 it is really very different from that of the true Rodentia ; the 

 food is exclusively vegetable, and the alimentary canal is 

 characterised by the presence of a capacious and complicated 

 ccecum. I distinguish this family by the name of Planti- 

 grades.' 1 



The following table exhibits these relations in a more con- 

 densed form ; and will give a good idea of what I consider to 

 be the most natural and philosophical arrangement of the 

 marsupials. Except the kangaroos, they are all of nocturnal 

 habits. 



Macropus 



MARSUPIALIA 



Marsupiated Mam- 

 mals 



I. Saltigrada 



with saltigrade extremities 



-mm- .7 1 jLF.Zl*l,# U Lt 1*0 



^rZ^S^\Hyp4ryrnnus 

 Peramelidee .J*"*™* 6 * 



^ and didelphoid teetn I ^h(Bropus 



( Myrmecobius 



II. Digitigrada \Phascogale 



with digitigrade extremities and didelphoid teeth dJasyuruS 



\ Thylacinus 



(DidelpMda..... { ^^ fef 



III. Cheirograda 



with pedimanous extremi- 

 ties 



and didelphoid teeth 



(Phalangista 

 Petaurus 

 Phascolarctos 



IV. Plantigrada Phascolomys 



with plantigrade extremities and rodent teeth 



Having thus traced the progressive history of the general 

 distribution of marsupial quadrupeds, inter se, it remains for 

 me to offer a few observations upon the rank which the main 

 group itself ought to occupy among the natural families of 

 the animal kingdom. M. De Blainville, in his view of the 

 subject, seems almost disposed to regard the marsupials as 

 forming a distinct class, parallel to and co-ordinate with the 

 Mammalia themselves ; and in this sentiment he has been, 

 to a certain extent, followed by Baron Cuvier. Illiger, less 

 happy in fixing their position in the graduated scale of ex- 

 istence, than in defining their generic differences, distributes 

 them throughout three different orders ; and Latreille, whilst 

 he regards the marsupials generally as forming a distinct na- 

 tural order, considers the Monotremata as a separate Class, 



