156 



able for their antero-posterior extent, ■vvhich dimension becomes ex- 

 cessive in the arboreal Potoroos of Ne\v Guinea. 



So far, therefove, as the affinities of a Marsupial quadruped are 

 indicated by its teeth, the position assigned to the Koala by Latreille*, 

 viz, next to the Phalangers, mušt be regarded as more natūrai than 

 thatwhich it occupies in the ' Rėgne Animal' of Cuvier, viz. bet\veen 

 the Kangaroos and Wombat. From the Kunyaroos the Koala difFers 

 in the presence of canines in the upper jaw ; and still more so from the 

 JVombat, M'hich has neither canines nor posterior incisors ; ■vvhereas 

 the Koala not only closely resembles the Phalangers and Petavrists 

 in the correspondence as to number, kind, and conformation of its 

 teeth, as compared with the functionally developed teeth of those 

 genera, but also agrees with them in the conformation of its di- 

 gestive organs, having asimple stomach, and a very long caecum. In 

 the Wombat, on the contrary, the caecum is short and wide, and has 

 a vermiform appendage. Both the Potoroos and Kangaroos diiFer 

 from the Koala and Phalangers in tlieir large sacculated stomach 

 and relatively shorter csecum ; but the Potoroos, in the comparative 

 simplicity of this organ, as well as in the presence of superior canine 

 teeth, have clearly the nearer affinity to the Koala. Since, more- 

 over, the Petaurists have canines in both jaws likę the Phalangers, 

 Avhile the Koala possesses them only in the upper jaw, the place of 

 the Petaurists should be bet\veen the Phalangers and Koala, and 

 not, as in Latreille's system, bet\veen the Kangaroos and Potoroos ; 

 and Professor 0\ven proposed to include the Koala with the Pha- 

 langers and Petaurists in one subdivision, and to join the Potoroos 

 with the Kangaroos to form anotlier and distinct primary group of 

 Marsupialia. 



• Fainilles Nat. du Regne Anim. p. 53. 



