MAMMALIA. 411 
Orper 2. MarsuptAttia. 
The order of Marsupialia, like that of Mdentata, includes animals differing 
very much from each other, although much more numerous in genera and 
species. A character common to all Marsupialia consists in the presence 
of two bones, called marsupial bones, attached to the anterior margin of the 
pelvis. ‘The same bones also exist in the Monotremata of the order Eden- 
tata. Another character is that of a pouch situated on the lower part of 
the abdomen of the female, into which are received the prematurely born 
young. This generative pouch is not possessed by the Monotremata, 
although implacental like the Marsupialia. Upon the signification and 
relative importance of both the marsupial bones and the pouch, we shall 
have a few words more to say hereafter. The bones of the cranium in 
Marsupialia do not anchylose, but remain permanently separated. The 
palatine part of the skull is imperfect, and presents large openings. 
The angle of the lower jaw is bent inwards, with one single exception, 
the Tarsipes. The structure of the brain presents also many peculiarities 
proper to the animals of this order, such as the absence of the corpus callo- 
sum and the imperfect division of the corpora quadrigemina. 
To a great diversity in their structure and organization corresponds a 
no less difference in their habits; some being carnivorous, some insecti 
vorous, and others frugivorous and herbivorous, in different degrees. The 
kangaroos are more especially grass and herb feeders; the burrowing 
wombats, root feeders; the phalangers eat the leaves, buds, and fruits of 
trees. 
Among Halmaturide, the true kangaroos, we find some species fitted 
for one region of country, and some for another; some prefer the 
swamps, and others the high table land. The Dendrolagus and Phalangis- 
tide inhabit trees, the wombats are subterranean, and the Chironectes 
aquatic. Of course, we find in several families nocturnal and diurnal 
genera. 
Brazil seems to be the country chiefly adapted by nature to the develop- 
ment of Didelphide. From this region they spread north as far as the 
United States, and south to the great river Plata, diminishing in number as 
they become more remote from this centre. Peru, Guiana, and Paraguay, 
the nearest provinces to Brazil, have about half a dozen species. 
Five zoological provinces may be established in Australia; an eastern, 
a western, a northern, and a southern; Van Diemen’s Land forms the fifth. 
The northern province has the greatest number of species peculiar to it, 
since, out of ten, eight are not found elsewhere. In the eastern province, 
the species are, for the most part, distinct from those of the opposite side of 
the continent; out of sixty species, eight are found in both provinces. 
South Australia, on the contrary, possesses a large proportion of species 
identical with those of other districts, four species only being peculiar to it. 
Sixteen species occur in common with western Australia, and fifteen with 
eastern Australia. The western province has two peculiar genera (Tarsipes 
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