MACROPOniD.K 161 



i lie blind, naked, helpless young creatures (which in the Gic.it 



Kangaroo (Fig. 53) scarcely exceed an inch in length) are attached 

 by their mouths to the nipples of the mother, and are fed by 

 milk injected into their stomach by the contraction of the muscle 

 covering the mammary gland. 



The Kangaroos are all vegetable feeders, browsing on grass and 

 various kinds of herbage, the smaller species also eating roots. 

 They are naturally timid, inoffensive creatures; but the larger ones 

 when hard pressed will turn and defend themselves, sometimes 

 killing a dog by grasping it in their fore paws, and inflicting 

 terrible wounds with the sharp claws of their powerful hind legs, 

 sustaining themselves meanwhile upon the tail. A few aberrant 

 forms are arboreal. The great majority are inhabitants of Australia 

 and Tasmania, forming one of the most prominent and characteristic 

 features of the fauna of these lands, and in the scenery of the 

 country, as well as the economy of nature, performing the part of 

 the deer and antelopes of other parts of the world, which are 

 entirely wanting in Australia. Kangaroos were very important 

 sources of food-supply to the natives, and are hunted by the colon- 

 ists, both for sport and with a view to their destruction, on account 

 of the damage they naturally do in consuming the grass, now 

 required for feeding cattle and sheep. Notwithstanding this, they 

 have in some districts increased in numbers, owing to the sup- 

 pression of their former enemies, the aborigines and the Dingo or 

 native dog. A few species are found in New Guinea and the 

 adjacent islands, Avhich belong, in the zoological sense, to the 

 Australian region. 



Before noticing the various generic types of the Macropodidce, a 

 few words are necessary in respect of the tooth-change, and we may 

 here quote the observations of Mr. 0. Thomas on this subject. 

 " The full dentition of the members of this family consists, in the 

 upper jaw, first of three incisors, then of a small canine (often, 

 however, suppressed, as in Fig. 55), and then of six cheek-teeth, 

 of which the second in the series is the only one which has a milk 

 or deciduous predecessor, and is therefore the one to be regarded 

 as the last premolar of the typical mammalian dentition. The 

 special characteristics that render the development and succession of 

 the teeth in the Macropodidce, and especially in the genus Macropux, 

 so puzzling to systematic zoologists, are : firstly, a general pro- 

 gression forwards in the jaw of the whole tooth-row, comparable to 

 that found elsewhere only in the Elephants and some Sirenians ; 

 and, secondly, the fact that before the tooth-change the first tooth 

 of the series (p 3) and the single milk-tooth (dm 4) placed next to 

 it, both of which fall out at the change, are respectively so very 

 similar in shape and size to the first and second teeth of the 

 permanent series, viz. the permanent premolar (p 4) and the first 



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