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marsupial genera, as J'hascolarctos, Phascolomys, Phalangista, Petaurus, Didelphys, 

 and Dasyurus, the tibia and fibula are so loosely connected together, and with the 

 tarsus, that the foot enjoys a movement of rotation analogous to the pronation and 

 supination of the hand: in the Petaurists, Phalangers, Opossums, and Koala the 

 inner toe, indeed, is so placed and organized as to perform the office of an opposable 

 thumb, whence these Marsupials have been termed Pedimana, or foot-handed. It is 

 to this prehensile power that the modifications of the fibula chiefly relate. In the 

 Wombat, Koala, Petaurists, and Phalangers it expands to nearly an equal size with 

 the tibia at the distal extremity, and takes a large share in the formation of the tarsal 

 joint; but the articular surface is slightly convex, while that of the tibia is slightly 

 concave. The proximal extremity of the fibula is also much enlarged, but compressed, 

 obliquely truncate, and gives off two tuberosities from its exterior surface ; to the 

 superior of these a large sesamoid bone is articulated. This homotype of the olecranon 

 is present in some other Marsupialia, e. g. Dasyurus macrurus, Didelphys ursina, and 

 Didelphys philander. 



The commencement of a degeneration of the foot, which is peculiar to, and highly 

 characteristic of, the diprotodont marsupial animals, is traceable in the Wombats, and 

 may be plainly discerned in the Petaurists, in the slenderness of the second and third 

 toes, as compared with the first, fourth, and fifth. In the Phalangers this diminution 

 of size is still more marked ; the second and third toes are also both of the same length, 

 and have no individual motion, being united together in the same sheath of integument 

 as far as the ungual phalanges. In the saltatorial genera of Diprotodonts the corre- 

 sponding toes, though reduced to almost filamentary slenderness, retain the usual 

 number of phalanges, the terminal ones being armed with claws, which appear as 

 appendages at the inner side of the foot, for the purpose of scratching the skin and 

 dressing the fur. The removal of the hallux commences in the Perameles. In one 

 species the metatarsal supports only a single rudimental phalanx, which reaches to the 

 end of the next metatarsal bone, and the entocuneiform 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 Macrotis lagotis the innermost toe is repre- 

 sented by a rudimental metatarsal bone, about one third the length of the adjoining 

 metatarsal. In Chceropus and the poephagous Marsupials no rudiment of the hallux 

 exists. The power of the foot is concentrated in Chceropus upon the fourth toe ; in 

 Kangaroos and Potoroos the fifth lends its aid, but is shorter than the fourth, which in 

 the Great Kangaroo is upwards of a foot in length, including the metatarsal bone and 

 the claw, which latter resembles an elongated hoof, but is three-sided and sharp- 

 pointed, like a bayonet. It is with this formidable weapon that the Kangaroo stabs 

 and rips open the abdomen of its assailant ; it will hold a powerful dog firmly during 

 the contest with the anterior extremities, and firmly supporting itself behind upon its 

 powerful tail, deliver its thrusts with the whole force of the hinder extremities. 



