MACROPODIDsE 



159 



occasionally prehensile ; stomach sacculated. Pouch large and 

 opening forwards. 



The Macropodidas or Kangaroos, taken as a whole, form a very 

 well-marked family, easily distinguished from the other members of 

 the suborder by their general conformation, and 

 by peculiarities in the structure of their limbs, 

 teeth, and other organs. They vary in size from 

 that of a sheep down to a small rabbit. The 

 head, especially in the larger species, is small, 

 compared with the rest of the body, and tapers 

 forward to the muzzle. The shoulders and fore 

 limbs are feebly developed, and the hind limbs 

 usually of disproportionate strength and magnitude, 

 which gives them a peculiarly awkward appearance 

 when moving about on all fours, as they occasion- 

 ally do when feeding. Rapid progression is, how- 

 ever, performed only by the powerful hind limbs, 

 the animal covering the ground by a series of 

 immense bounds, during which the fore part of the 

 body is inclined forwards, and balanced by the 

 long, strong, and tapering tail, which is carried 

 horizontally backwards. When not moving they 

 often assume a perfectly upright position, the tail 

 aiding the two hind legs to form a sort of support- 

 ing tripod, and the front limbs dangling by the 

 side of the chest. This position gives full scope 

 for the senses of sight, hearing, and smell to warn 

 of the approach of enemies, from which these 

 animals save themselves by their bounding flight. 

 The fore paws have five distinct digits, each armed 

 with a strong curved claw. 



The hind foot (Fig. 52), as being a typical 

 example of the syndactylous modification, may be 

 noticed in some detail. It is extremely long and 

 narrow, and (with only one exception) without any 

 hallux or great toe. It consists mainly of one very large and strong 

 toe, corresponding to the fourth of the human or other typically 

 developed foot, ending in a strong, curved, and pointed claw. 

 Close to the outer side of this lies a smaller fifth digit, and to the 

 inner side two excessively slender toes (the second and third), 

 bound together almost to the extremity in a common integument. 

 The two little claws of these toes, projecting together from the 

 skin, may be of use in scratching and cleaning the fur of the 

 animal, but the toes themselves must have quite lost all connexion 

 with the functions of support or progression. 



The dentition of the Kangaroos, functionally considered, 



FIG. 52. Skeleton 

 of right hind foot of 

 Kangaroo. 



