SKELETON OF MAESUPIALIA. 363 



beyond the integument, they look like little appendages at the 

 inner side of the foot for the purpose of scratching the skin and 

 dressing the fur, to which offices they are exclusively designed. 

 The removal of the innermost toe, corresponding mth our great 

 toe and the hallux of the Pedimana, commences in the Perameles. 

 In one species I find the metatarsal bone of this toe supports only 

 a single rudimental phalanx which reaches to the end of the next 

 metatarsal bone, and the internal cuneiform bone is elongated. 

 In another species the internal toe is as long as the abortive 

 second and third toes, and has two phalanges, the last of which is 

 divided by the longitudinal fissure characteristic of the ungual 

 phalanges in this genus. In the Perameles lagotis the innermost 

 toe is represented by a rudimentary metatarsal bone, about one- 

 third the length of the adjoining metatarsal. 



In the Poephagous Marsupials no rudiment of the innermost 

 toe exists. The power of the foot is concentrated in all these 

 genera on the fourth and fifth or two outer toes, but especially 

 the fourth, which, in the Great Kangaroo, is upwards of a foot in 

 length, including the metatarsal bone and the claw. This for- 

 midable weapon resembles an elongated hoof, but is three-sided 

 and sharp-pointed like a bayonet, and with it the Kangaroo stabs 

 and rips open the abdomen of its assailant: with the anterior 

 extremities it will hold a powerful dog firmly during the at- 

 tack, and firmly supporting itself behind upon its powerful tail, 

 deliver its thrusts Avith the whole force of the hinder extremities. 

 The cuboid bone which supports the two outer metatarsals is 

 proportionally developed. The internal cuneiform bone is pre- 

 sent, though the toe which is usually articulated to it is Avanting. 

 It is also the largest of the three, and assists in supporting the 

 second metatarsal ; posteriorly it is joined with the navicular and 

 external cuneiform bones, the small middle cuneiform occupying 

 the space between the external and internal wedge-bones and the 

 proximal extremities of the two abortive metatarsals. The great 

 or fourth metatarsal is straight and somewhat flattened ; the ex- 

 ternal one is compressed and slightly bent outward; the toe 

 which this supports is armed with a claw similar to the large one, 

 but the ungual phalanx does not reach to the end of the second 

 phalanx of the fourth toe, and the whole digit is proportionally 

 weaker. In the climbing Potoroos (^Hypsijwymnus ursinus and 

 Hypsiprymnus dorcocephalus), the two outer toes are propor- 

 tionally shorter than in the leaping species, and are terminated 

 by curved claws by which they gain a better hold on the branches 

 and inequalities of trees. 



