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the astragalus rests upon the calcaneum : a greater part of the super- 

 incumbent pressure is transmitted by a transversely extendecl convex 

 anterior surface to the scaphoid and cuboid bones. Tliis forrn of the 

 astragalus is also characteristic of the Koala, Petaurists.Dasyures, and 

 the Pedimanous Marsupials. In the Kangaroos, Potoroos, and Pera- 

 meles which have the pedes saltatorii, the fibular articular surface 

 of the astragalus is bent down as usual, at nearly right angles with 

 the upper tibial surface. The calcaneum presents a ridge on the 

 outer surface which serves to sustain the pressure of the external 

 malleolus, which is not articulated to the side of the astragalus. 

 The internal surface which joins the astragalus is continuous \vith 

 the anterior slightly concave surface which articulates with the cu- 

 boides. The posterior part of the bone is compressed ; it projects back- 

 wards for nearly an inch, and is slightly bent downwards and inwards. 

 This part is relatively shorter in the Koala, Phalangers, Opossums, 

 and Petaurists ; but is as strongly developed in the Dasyures as in 

 the Wombat. In the Dasyurus macrurus, I observe a small sesamoid 

 bone wedged in between the astragalus, tibia, and fibula, at the back 

 part of the joint. In the Petaurus tagnanoides, there is a supple- 

 mental taršai bone wedged in between the naviculare and cuboides in 

 the plantar surface. In the Wombat the scaplioid, cuboid, and the 

 three cuneiform bones, have the ordinary uses and relative positions. 

 " The analogy of the carpal and taršai bones is very clearly illus- 

 trated in this animal. The anchylosed naviculare and lunare of the 

 hand correspond with the astragalus and naviculare of the foot, 

 transferring the pressure of the focile majus upon the three inner- 

 most bones of the second series. The long backward projecting pisi- 

 form bone of the wrist closely resembles the posterior process of the 

 os calcis ; the articular portion or body of the os calcls corresponds 

 with the cuneiform ; the large unciform represents the cuboides, 

 and performs the šame function, supporting the two outer digits : 

 the three cuneiform bones are obviously analogous to the trapeziiim, 

 trapezoides, and os magnum. The internal cuneiforme bone is the 

 largest of the three in the Wombat, although it supports the smallest 

 of the toes. It is of course more developed in the Pedimanous Mar- 

 supials, where it supports a large and opposable thumb. In the 

 ■VVombat the metatarsals progressively increase in length and breadth 

 from the innermost to the fourth ; the fifth or outermost metatarsal 

 is somewhat shorter, but tvvice as thick, and it sends ofF a strong 

 obtuse process from the inside of its proximal end. The innermost 

 metatarsal supports only a single phalanx ; the ręst are succeeded hy 

 three phalanges each, progressively increasing in thickness to the 

 outermost; the ungueal phalanges are elongated, gently curved 

 downwards, and gradually diminish to a point. In the Dasyures the 

 innermost toe has two phalanges, but it is the most slender, and 

 does not exceed in length the metatarsal bone of the second toe. 

 In the Petaurists it is rather shorter than the other digits, but is the 

 strongest; the toes are set wide apart in this genus. In the Opos- 

 sums and Phalangers the inner metatarsal bone is directed inwards 

 apart from the ręst, and together with the first phalanx, is broadand 



