MAMMALIA. 411 



Order 2. Marsupialia. 



The order of Marsupialia, like that of Edentata, 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 7narsupial hones, 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 pai't 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 quadrige?nina. 



To a great diversity in their structure and organization correspond.^ 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 Halmaturidae, 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- 

 tidee 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 Didelphidffi. 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 Diernen'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 



615 



