MACROPODID.E 159 
oceasionally prehensile ; stomach sacculated. Pouch large and 
opening forwards. 
The JMucropodide or Kangaroos, taken as a whole, form a very 
well-marked family, easily distinguished from the other members of 
the suborder by their general conformation, and 
by peculiarities in the structure of their limbs, 
teeth, and other organs. They vary in size from 
that of a sheep down to a small rabbit. The 
head, especially in the larger species, is small, 
compared with the rest of the body, and tapers 
forward to the muzzle. The shoulders and fore 
limbs are feebly developed, and the hind limbs 
usually of disproportionate strength and magnitude, 
which gives them a peculiarly awkward appearance 
when moving about on all fours, as they occasion- 
ally do when feeding. Rapid progression is, how- 
ever, performed only by the powerful hind limbs, 
the animal covering the ground by a series of 
immense bounds, during which the fore part of the 
body is inclined forwards, and balanced by the 
long, strong, and tapering tail, which is carried 
horizontally backwards. When not moving they 
often assume a perfectly upright position, the tail 
aiding the two hind legs to form a sort of support- 
ing tripod, and the front limbs dangling hy the 
side of the chest. This position gives full scope 
for the senses of sight, hearing, and smell to warn 
of the approach of enemies, from which these 
animals save themselves by their bounding flight. 
The fore paws have five distinct digits, each armed 
with a strong curved claw. 
The hind foot (Fig. 52), as being a typical 
example of the syndactylous modification, may be — Fre. 52,—Skeleton 
noticed in some detail. It is extremely long and $f rsht hind foot of 
narrow, and (with only one exception) without any ~~" 
hallux or great toe. It consists mainly of one very large and strong 
toe, corresponding to the fourth of the human or other typically 
developed foot, ending in a strong, curved, and pointed claw. 
Close to the outer side of this lies a smaller fifth digit, and to the 
inner side two excessively slender toes (the second and third), 
bound together almost to the extremity in a common integument. 
The two little claws of these toes, projecting together from the 
skin, may be of use in scratching and cleaning the fur of the 
animal, but the toes themselves must have quite lost all connexion 
with the functions of support or progression. 
The dentition of the Kangaroos, functionally considered, 
