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. 
Hyrsiprymnus, Lllig.* 
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 these 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 cecum is rounded, and of a middling size. 
Hyps. minor; Macropus minor, Shaw; White, Bot. Bay, 286; 
Voy. de Freycin. pl. 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—Hatmaturvs, Illig.t 
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 cecum, 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. 
* Ipsiprumnos; i, e. raised behind. + Halmaturus, tail fit for leaping. 
