497 



(ib. ib. k), from which a narrower rough tract is continued downward (distad) far back- 

 ward (plantad), assuming more or less the character of a groove to, or near to, midway 

 down the shaft. 



The depression (k) is bounded behind (plantad) by the peroneal process, the groove 

 of which (g) and the sesamoid surface (h) beneath the groove slope upward and outward 

 (fibulad). 



On the outer (fibular) surface of the proximal end there is a transversely elongate 

 concave articular surface (ib. fig. 1, v, and Plate CXVIII. fig. 2, v), less narrow ver- 

 tically, at the middle, than is the opposite (bilobed) surface (ib. m, n, fig. 1). Below 

 the articular surface is a transversely subelongate rough depression from the hinder 

 (plantar) end, of which the shallow rough tract (ib. fig. 2, u) for ligamentous attach- 

 ment of the fifth metatarsal is continued about two thirds down the shaft. These 

 characters distinguish the inner tibial from the outer fibular side of the shaft of this 

 metatarsal, and determine the foot, right or left, to which it belongs. In the descrip- 

 tion of the Plates the bone is called right or left as it there appears, but most of the 

 figures were drawn without reversing from bones of the opposite foot. 



A considerable number of metatarsal bones of Kangaroos (Macropodidce), chiefly of 

 the toe (ir), has now accumulated on my hands from kind contributors of fossils in 

 Australia. Not any of the specimens, however, have been discovered so associated with 

 other remains of an individual of a species the characters of which are known, or were so 

 recognizable as to justify more than probable or provisional ascription to such species. 



It would seem that the conditions of association are scarcely to be expected in the 

 beds of the creeks and rivers of Queensland which have yielded the majority of these 

 metatarsal specimens. Their matrix seems to be made of materials transported from 

 those drift-like deposits through which the well-sinkers bore for a hundred feet deep 

 or more in quest of spring-water, and in the course of which borings the least fractured 

 and abraded mammalian fossils, and seemingly the least disturbed after imbedment, 

 have hitherto been obtained. 



It will be understood, therefore, that the results of my attempts to associate any of 

 the metatarsal bones with species or genera previously defined by dental and cranial 

 characters are tentative, resting on analogical grounds and inferences stated, and must 

 be received subject to confirmation or otherwise by the more fortunate finders of a 

 sufficient proportion of an entire skeleton to demonstrate a foot to have been part of 

 the same animal as the associated jaws and teeth. 



I have divided, in the first place, the metatarsals best agreeing in proportions with 

 those of the large existing Kangaroos from those that deviate in a marked degree from 

 such proportions, and which indicate a less extremely modified form and length of the 

 hind foot. 



Commencing with the first group, I begin the comparisons with the metatarsals which 

 are nearest in size to those of existing Kangaroos, such as Macropus major and 

 Osphranter rufus. 



