141 



Koala, or the carnivorous Dasyure, save in relative size. They jnc- 

 seut the greatest proportional strength in the Wombat, and the 

 greatest proportional length and slenderness in the Petaurists or 

 Flying Opossums, in which the extremities are subservient to the 

 support of a dermal parachute. They are also long and slender 

 in the Koala. In general the radius and ulna run nearly parallel, 

 and the interosseous space is very tritling : it is widest in the Po- 

 toroos. The olecranon is well developed in all the Marsupiata. In 

 the Virginian Opossum and Petaurists, we find it more bent for- 

 wards upon the rest of the ulna, than in the other Marsupials. In 

 the Wombat, where the acromion is the strongest, and rises an inch 

 and a half above the articular cavity of the ulna, it is extended in 

 the axis of the bone. The distal end of the radius in this animal is 

 articulated to a broad bone representing the os scaphoides and os 

 lunare. The ulna, which in the same animal converges towards a 

 point at its distal end, has that point received in a depression formed 

 by the cuneiform and pisiform bones ; these are bound together by 

 strong ligaments ; and the latter then extends downwards and back- 

 wards for two-thirds of an inch. The second row of the carpus con- 

 sists of five bones. The trapezium supports the inner digit, and has a 

 small sesamoid bone articulated to its radial surface. The trapezoides 

 is articulated to the index digit, and is wedged between the scapho- 

 lunar bone and os magnum \\\n.% forms an obHque articular surface 

 for the middle digit ; but the largest of the second series of carpal 

 bones is the cuneiform, which sends downwards an obtuse rounded 

 process, and receives the articular surface of the fifth and the outer 

 half of that of the fourth digit ; the remainder of which abuts against 

 the oblique proximal extremity of the middle metatarsal bone. The five 

 metatarsal bones are all thick and short, but chiefly so the outermost. 



" The innermost digit has two phalanges, the remainder three; the 

 ungueal phalanx is conical, curved, convex above, expanded at the 

 base, and simple at the opposite extremity. In the Perameles the 

 ungueal phalanx of the three middle digits of the hand, and of the 

 two outer digits of the foot, are split at the extremity by a longitudinal 

 fissure, commencing at the upper part of the base. This structure, 

 which characterizes the ungueal phalanges in the placental Pangolins, 

 has not been hitherto met with in other marsupial genera. It would 

 be interesting to examine the skeleton of the newly described ge- 

 nera Myrmecobius and Charopus with reference to this structure. 



"The terminal phalanges of the Koala are large, much com- 

 pressed, and curved ; the concave articular surface is not situated, 

 as in the cats, on the lower part of the proximal end, but, as in the 

 sloths, at the upper. The claws which they support are long. 



" In the great Kangaroo the first row of the carpus is composed, 

 as in the Wombat, of three bones ; but the apex of the ulna rotates 

 in a cavity formed exclusively by the cuneiforme. There are four bones 

 in the second row. of which the cuneiform is by far the largest, and 

 supports a part of the middle, as well as the two outer digits. In 

 Potoroos I find but three bones in the distal series of the tarsus, 

 the trapezoides being wanting, and its place in one species l)eing 



