106 
LOWER MAMMAL GALLERY. 
former, in that Marsupials include species representative of the 
herbivorous, carnivorous, and insectivorous types of other 
Mammals. 
The females of most Marsupials possess a pouch of skin 
on the under part of their bodies, which gives the name 
to the order. In this pouch the young, which are in a very 
imperfect condition when born, continue their development, 
clinging at first firmly to the nipples, and using the pouch for 
a long time afterwards as a place of refuge until able to take 
care of themselves. In fact, functionally, the pouch of a 
Marsupial corresponds to the nest of a bird. 
The principal characteristic by which the skeletons of Marsu- 
pials differ from those of all the previous orders is the presence 
of a pair of long slender bones, attached to the front edge of 
the pelvis. These are known as the marsupial hones,^^ owing 
to their proximity to the external pouch *. In their skulls the 
Marsupials differ from other Mammals by having the angle of 
the lower jaw much bent inwards, and forming a well-marked 
internal process. Teeth are always present, and separable into 
different classes, but, with the exception of one premolar, not 
preceded by milk-teeth. The incisors are generally unequal in 
number in the two jaws, and range from f to f. The dorso- 
lumbar vertebrae are invariably 19. 
[Cases Marsupials are divided primarily into two great groups : in 
69 & 69 *.] the first, as in the Rodents and Ungulates, the incisors are few 
in number, but large and powerful, and the canines, at least in 
the lower jaw, are either entirely absent or small and rudi- 
mentary; while the second possess, like the Placental Carnivora, 
small and numerous incisors and large and sharp canines. The 
former are called “ Diprotodont t and the latter Poly- 
pro rod onU’ t. 
To the former group belong Kangaroos, Phalangers or 
Australian Opossums, and Wombats, which, with but few 
exceptions, live chiefly upon vegetable food ; to the latter, 
* They are absent in one genus only, Thylacynus, and in some American 
Opossums. 
•j- “ With two front teeth. ’ 
t “ With many front teeth.’ 
