1282 CLASS MAMMALIA. 



Family Phascolomyid^e. — This family is now represented only 

 by the genus Phascolomys, or Wombats ; in which the dental formula 



is /. -j C. -, Pm. -, M. -, and all the teeth grow from persistent 



i o i 4 



pulps. The true molars have curved crowns consisting of two sub- 

 equal lobes, while the premolar has only a single lobe, and is not 

 preceded by a milk-tooth. The mandible (figs. 1152, 1153) is 

 characterised by having a pit and perforation in the masseteric 

 fossa. The fore and hind limbs are of equal length, the former 

 being of great strength in accordance with the fossorial habits of 

 the genus ; and the humerus has a foramen. There are five digits 

 in the manus, all of which are provided with long curved claws, and 

 are of subequal size ; but in the pes the hallux is imperfect, and 

 the three middle digits are of nearly equal size, and partly enclosed 

 in a common integument. Three existing species of Wombat are 

 known, which are divided into two groups according to the char- 



Fig. 1 153. — Left lateral view of skull of Wombat (Phascolomys latifrons). Reduced. 

 Australia. 



acters of the skull and teeth ; none of them being of large size. In 

 the Pleistocene of Australia we meet with remains not only of these 

 existing species, but also with several extinct types, one of which 

 was of considerably larger dimensions. In the same deposits are 

 also found remains of the extinct genus Phascolonus (with which 

 the so-called Sceparnodon appears to be identical), characterised by 

 certain peculiarities in the incisors. The one known species prob- 

 ably attained the dimensions of a Tapir, although of considerably 

 stouter build. 



Family Nototheriid^e. — This family is represented only by a 

 single definitely known genus from the Australian Pleistocene de- 

 scribed as Nototherium. 1 This includes one (or possibly more) large 



1 It has recently been suggested that the figured skull does not belong to Noto- 

 therium, and that it should be termed Zygomaturus ; but this view is not sup- 



