114 MAMMALIA. 



toes united to the hind feet of the second ; but the posterior thumbs and 

 inferior canini are wanting. It contains but a single genus. 



Hypsiprymnus, Illig.* 



The Potoroos are the last animals of this family which retain any trait 

 of the general characters of the Carnaria. Their teeth are nearly the 

 same as those of the Phalangers, and they still have pointed canines 

 above. The two superior middle incisors are pointed, and longer than 

 the others; the inferior ones are but two, and project forwards. In front 

 they have a long trenchant denticulated molar, followed by four others, 

 bristling with four blunt tubercles. What particularly distinguishes these 

 animals is their hind legs, which are much larger in proportion than the 

 fore ones, that have no thumbs, and the two first toes united as far as the 

 nail ; so that, at a first glance, it seems as though there were but three 

 toes, of which the inner one has two nails. They frequently walk upon 

 two feet, at which times they employ their long and strong tail to support 

 themselves. They have then the form and habits of the Kanguroos, from 

 which they only differ in their superior canine tooth. They are frugivo- 

 rous ; their stomach is large, divided into two sacs, and has several infla- 

 tions ; but their caecum is rounded, and of a middling size. 



Hyps, minor; Macropus minor, Shaw; "N^Qiite, Bot. Bay, 286; 

 Voy. de Freycin. pi. 10. (The Kanguroo Rat.) Size of a small 

 rabbit ; of a mouse-grey. From New Holland, where it is called Po- 

 toroo. It is the only species known. 



The fourth subdivision only differs from the third in the absence of all 

 canines whatsoever. These are — 



Macropus, Shaw — Halmaturus, Illig.-f 



The Kanguroos, which present all the characters we have just assigned 

 to the preceding genus, except that the superior canine is wanting, and 

 that their middle incisors do not project beyond the others. The inequa- 

 lity of their legs is still greater, so that on all fours they can only walk 

 slowly and with difficulty ; they make vigorous leaps, however, on their 

 hind feet, the great middle nail of which (almost in the shape of a hoof) 

 also serves them for purposes of defence : for, by supporting themselves 

 on one foot and their enormous tail, they can inflict a severe blow with 

 the foot which is at liberty. They are very gentle herbivorous animals, 

 their grinders presenting mere transverse ridges. They have five teeth 

 in all, the front ones being more or less trenchant, and falling out with 

 age ; so that in old kanguroos we frequently find but three. Their sto- 

 mach consists of two long sacs, that are inflated at several places, like a 

 colon. The csecum, also, is large, and has inflations. The radius al- 

 lows a complete rotation of the fore-arm. 



In these two genera the penis is not bifurcated, but the female organs 

 of generation are similar to those of other Marsupialia. 



Tpslprumms ; i. e. raised behind. f Halmaturus, tail fit for leaping. 



