POLYPROTODONTIA. 723 



or insectivorous in diet. The limbs have five clawed digits ; 

 the hallux is opposable. The tail is generally long, and often 

 prehensile. The stomach is simple ; the oecum small. The 

 pouch is generally absent, but the young are often carried on 

 the back of the mother, their tails coiled round hers. Dentition, 



5134 



4134' 



Examples. The Virginian or crab-eating opossum (Didelphys 

 niarsupialis], with a pouch ; the woolly opossum (D. lanigera) ; 

 the aquatic Yapock \Chironectes\ which feeds on fish and 

 smaller water animals. 



Family Dasyuridie. Carnivorous or insectivorous Marsupials. The 



limbs have clawed digits, five in front, four or five behind. The 



canines are generally large. The stomach is simple ; there is no 



caecum. 



Examples. The Tasmanian wolf (T/iylacinns), of dog-like form, 



dentition \ 34 , and the Dasyure (Dasynnts], civet-like, den- 

 tition 4 24 , are specialised as carnivores. The members of the 

 3124' 



genus Phascogale are small and insectivorous. The banded 

 ant-eater (Myrmecobius) of \V. and S. Australia, a somewhat 

 squirrel-like animal, has a long thread-like protrusible tongue, 



and more teeth than any other Marsupial 4 ,. It differs 



3135 or 6 



markedly from the other members of the family. 



Family Notoryctidse. - - This family has been erected for the 

 recently-discovered mole-like Marsupial (Notoryctes typhlops], 

 found in the sandy deserts of S. Australia. It lives underground, 

 is a rapid burrower, and in its rudimentary eyes, keeled sternum, 

 and some other respects, markedly resembles the Eutherian mole. 

 It is thus a good illustration of " convergence," i.e. the appear- 

 ance of similar characters in forms not nearly related, apparently 

 in indirect response to similar conditions of life. 



Family Peramelidse. The burrowing bandicoots, all small in size, 

 insectivorous or omnivorous in diet. In the fore-feet two or 

 three of the middle toes are well developed and clawed, the 

 others being rudimentary ; in the hind-feet the hallux is small or 

 absent, the second and third toes are very slender and united 

 in the same fold of skin, the fourth toe is very large, the fifth 

 smaller, the whole foot suggesting that of the kangaroo. The 

 stomach is simple ; the crocum not large. Clavicles are absent. 



Dentition, 



4 or 5134 



3 134 



Examples. The true bandicoot (Perawe/es), remarkable for its 

 allantoic placenta; the native rabbit (Peragah lagolis}', the 

 rat-like Chceroptis. 



