160 WARSUPIALIA 
consists of sharp-edged incisors. most fully developed near the 
median line of the mouth, for the purpose of cropping the various 
kinds of herbage on which they feed. and ridged and tuberculated 
molars for crushing it, there beinz no tusks or canines for offensive 
or defensive purposes. 
The number of vertebre is—in the cervical region 7, dorsal 13. 
lumbar 6, sacral 2. caudal varying according to the length of the 
tail, but generally from 21 to 25. In the fore limb the clavicle 
and the radius and ulna are well developed. allowing of considerable 
freedom cf motion of the hand. The pelvis has large epipubic or 
“marsupial” hones. The femur is short. and the tibia and fibula 
are of great length. as is the foot, the whole of which is applied to 
the <round when the animal is at rest in the upright position. 
The stomach is of large size. and very complex, its walls being 
puckered up by longitudinal muscular bands into a great number ot 
sacculi, like those of the human colon. The alimentary canal Is 
long. and the cxcum well developed. All the species have a 
marsupium or pouch formed by a fold of the skin of the abdomen 
covering the mammary glands with their four nipples. In this 
pouch the young are placed as soon as they are born: there their 
growth and development proceeds; and to it they resort tempor- 
arily for the purpose of shelter, concealment, or transport, for some 
time after they are able to run and jump about the ground and 
feed upon the same herbage which forms the nourishment of the 
parent. During the early period of their sojown in the pouch, 
