XXV] METATHERIA 663 



somewhat resembling Rabbits and Hares in their appearance but with 

 pointed muzzles ; they are remarkable in possessing a type of foot 

 characteristic of the Diprotodontia. The NOTORYCTIDAE include the 

 single genus Notwyctes, which in habits and appearance resembles 

 the Mole, a similar mode of life having brought about similar 

 modifications of structure. 



The order DIPROTODONTIA includes a number of species confined, 

 with one exception, to Australia and the neighbouring islands. 

 One species, the only living representative of the family EPANOR- 

 THIDAE, has been recently found in South America. This animal, 

 which has received the name Caenolestes uliginosus, has feet like 

 the DIDELPHYIDAE, and this circumstance renders it possible that 

 it has been independently evolved from that family, whereas the 

 other members of the order seem to have been derived from 

 forms like the PERAMELIDAE. The typical Diprotodontia have the 

 second, third, fourth and fifth toes of the hind-foot united by a web 

 of skin. The fourth is the strongest toe, the fifth is a little shorter, 

 but usually nearly as stout as the fourth; the second and third, 

 though as long as the fourth, are much more slender, while the 

 great toe is often rudimentary. Exclusive of the EPANORTHIDAE 

 there are three families in the sub-order. The first family, the 

 PHASCOLOMYIDAE, consists of one genus, Phascolomys, the Wombat, 

 represented by three species. The PHASCOLOMYIDAE are distin- 

 guished by possessing only one incisor on each side of the upper 

 jaw, and as both upper .and lower incisors are chisel-shaped the 

 dentition resembles that of a Beaver or Rat. Wombats are heavy 

 animals with a shuffling gait, about the size and appearance of a 

 Badger. 



The second family, the PHALANGERIDAE, or Australian Opossums, 

 have normally three incisors on each side of the upper jaw; the 

 fore- and hind-limbs are of about the same size and the great toe 

 is prehensile. These are small animals which like Squirrels live in 

 trees, and several species possess a parachute-like membrane ex- 

 tending from fore- to hind-limb, by the aid of which they sustain 

 themselves in the air during their great leaps from tree to tree. 

 Phascolarctus, the so-called Native Bear, is a clumsy tailless Pha- 

 langer, in which the prehensile great toe is specially well developed. 

 The MACROPODIDAE, or Kangaroos, are the most peculiar family of 

 Diprotodontia, and indeed of the Metatheria. They resemble the 

 Phalangeridae in having three upper incisors on each side, but differ 

 totally in the structure of the limbs. The fore-limbs are so small 



