VERTEBRATA. 



243 



The affinity of the Iraplacentalia to the Sauria is shown in parts 

 of the skeleton. One reptilian character is that the bones of the 

 skull remain in a state of permanent separation. 



The Marsupials are amongst the oldest known mammals, and 

 some were of very large size. Diprotodon australis had a skull 

 three feet in length. Several species are found in the British 

 Mesozoic formations. 



The recent species are mostly Australian, but they were once 

 common in Europe. Didelphidse are American. Owen has di- 

 vided them into five "tribes," all of which are represented among 

 the monodelphous Mammalia. Eeversing the descending order, 

 these tribes are : 



EHIZOPHAGA. Two scalprifqrm incisors in both jaws ; 110 



canines ; short cgecum. 

 POEPHAGA. Anterior incisors large and long in both jaws ; 



canines in the upper jaw only, or wanting ; a long 



caecum. 

 CARPOPHAGA. Anterior incisors large and long in both jaws 



canines inconstant ; a long caecum. 

 ENTOMOPHAGA. Three kinds of teeth in both jaws ; a 



caecum. 

 SARCOPHAGA. Three kinds of teeth in both jaws ; no caecum. 



RHIZOPHAGA. 



Phascolomyida. 

 Phascolomys 

 (Wombat). 



^Diprotodon. 



POEPHAGA. 



CARPOPHAGA. 



Phascolarctida. 

 Phascolarctos 

 (Koala). 



Pha langistidfB. 

 Cuscus. 

 Phalangista. 

 Acrobata. 

 Petaurus. 



Macropodidce. 

 Dendrolagus. 

 Hypsiprymnus ENTOMOPHAGA. 



(Kangaroo-rat). 

 Macropus=Halma- Peramelida). 



turu8(Kaugaroo). Cbceropus, 



Perameles (Bandi- 

 Hypsiprymnodon. coot). 



Tarsipes. 



Didelphyida. 

 Didelphys (Opossum). 

 Chironectes. 



SARCOPHAGA. 



Dasyuridce, 

 Thylacinus. 

 Dasyurus. 

 Myrmecobius. 

 Phascogale. 



*Pha8Colotherium. 

 *Microlestes. 



*Thylacoleo. 



