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its anterior and internal angle, which becomes convex in every direction, 

 is directly continued into the anterior scaphoidal convexity, which sweeps 

 round a deep and rough depression, dividing the outer and anterior part 

 of the tibial trochlea from the corresponding half of the scaphoidal con- 

 vexity ; this has the greatest vertical extent at its inner part, where it is 

 separated by a narrow rough transverse channel from the part which 

 rested upon the os calcis. The calcaneal surface is single and covers 

 almost the whole of the under part of the astragalus : the greatest pro- 

 portion of it is flat and reniform ; an angular tuberosity or process being 

 continued from the concave margin, where the pelvis of the kidney, to 

 pursue the comparison, would be situated. This process must be received 

 into a corresponding depression at the outer part of the articular surface 

 upon the calcaneum. On the inner margin of the flat calcaneal surface 

 opposite the tuberosity, a small triangular flattened surface is continued 

 upwards upon the inner and posterior side of the astragalus, and nearly 

 touches the inner and posterior angle of the tibial trochlea. 



The length of this fossil astragalus is four inches eight lines ; its 

 breadth is three inches five lines ; its depth (at the base of the sca- 

 phoidal convexity) is two inches and a half. We look in vain amongst the 

 Pachyderms with astragali of corresponding dimensions for the uniform 

 and prominent convexity of the anterior articulation, for its continuation 

 with the tibial trochlea, and for the single and uninterrupted calcaneal 

 tract on the lower surface of the bone. The Proboscidians, which ap- 

 proach nearest the present fossil in the depressed form of the astragalus 

 and the flattening of the calcaneal articulation, have that articulation 

 divided into two surfaces by a deep and rough groove : the scaphoidal 

 surface is likewise similarly divided from the tibial trochlea ; and no 

 Pachyderm has the upper articular surface of the astragalus traversed 

 by an antero-posterior or longitudinal ridge, dividing it from an almost 

 horizontal facet for the support of the end of the fibula. 



The peculiar form of the astragalus in the Ruminants, and especially 

 the trochlear character of the anterior or scapho-cuboidal surface, place it 

 beyond the pale of comparison. In all^ the placental Carnivora the sca- 

 phoidal convexity is pretty uniform, and occupies the anterior extremity 



