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occujiied by the proximal end of the second metatarsal bone, which 

 articulates with the os magnum. In the Peranieles there are four 

 bones in the distal series, although the hand is less perfect in this 

 than in any other marsupial genus, the three middle toes only being 

 fully developed. In the Petaurists, the carpus is chiefly remarkable for 

 the length of the os pisiforme. It would be tedious to dwell on the 

 minor differences observable in the bony structure of the hand in 

 other Marsupiata. I shall therefore only observe that, though the inner 

 digit is not situated like a thumb, yet that the lingers enjoy much 

 lateral motion ; and that those at the outer can be opposed to those at 

 the inner side, so as to grasp an object and perform in a secondary 

 degree the function of a hand. In the Koala the two inner digits are 

 more decidedly opposed to the three outerones thanin any other climb- 

 ing Marsupial. But some of the Phalanges, as the Ph. Cookii and 

 Ph. gliriformis of Bell, present in a slight degree the same disposi- 

 tions of the fingers, by which two out of the five have the opposable 

 proijerties of a thumb— a structure for which we seek in vain among 

 the placental Mammalia, but which we have repeated in the prehen- 

 sile extremities of the Chameleon. 



' ' The pelvis in the mature Marsupial is composed of the os 

 sacrum, the two ossa iiinominata, and the characteriscic supplemental 

 bones attached to the pubes, called by Tyson the ossa mursupiaUa, 

 or Janitores marsvpii. 



" We seek in vain for any relationship between the size of the pel- 

 vis and that of the new-born young, the minuteness of which is so 

 characteristic of the present tribe of animals. The diameters both 

 of the area and the apertures of the pelvic canal are considerable, 

 but more especially so in those Marsupialia which have the hinder 

 extremities disproportionally large, as also in the Wombat, where 

 the pelvis is remarkable for its width. The pelvis is relatively small- 

 est in the Petaurists. The anterior bony arches formed by the ossa 

 pubis and the ischia are always complete ; and the interspace between 

 these arches is divided, as in other Mammalia, into the two obturator 

 foramina, by an osseous bridge continued from the pubes to the ischium 

 on each side of the sytnp'iysis. 



" In the Kangaroos, Potoroos, Phalangers, and Opossums, the 

 ischia offer an elongated prismatic form. They are straight in the 

 Opossum, but gently curved outwards in the other marsupial genera. 

 In the Dasyures there is a longitudinal groove widening upwards in 

 place of the angle at the middle of the exterior surface of the ilium. 



" The ilia in the Petaurists are simplj' compressed from side to 

 side. They are broader and flatter in the Pei-ameles, and their plane 

 is turned outwards. But the most remarkable form of the ilia is 

 seen in the Wombat, in which they are considerably bent outwards 

 at their anterior extremity. 



" In the Kangaroos and Potoroos the eye is arrested by a strong 

 process given off from near the middle of the ilio-pubic ridge ; and 

 this process may be observed less developed in the other Marsupiata. 



" The tuberosity of the ischia inclines outwards in a very slight 

 degree in the Dasyures, Opossums, Phalangers, Petaurists, and Pe- 



