322 SCOTT. [Vol. V. 



considerable antero-posterior depth. The internal side is rugose 

 and marked by a deep oblique groove, which, however, does not 

 appear to be a tendinal sulcus ; the posterior face is also rugose, 

 but less transversely extended than in the horse, where this face 

 forms a hook projecting toward the ulnar side. The proximal 

 facet for the radius has a greater antero-posterior extent than 

 that of the lunar or cuneiform ; it is broader and slightly convex 

 in front, narrower and concave behind. On the ulnar side of the 

 scaphoid there are two facets for the lunar, of which the inferior 

 is less distinct than in the horse, and the interval between the 

 scaphoid and lunar not so large as in that animal. The distal 

 surface of the scaphoid exhibits three articular facets, arranged 

 one behind the other; of these the anterior and largest one is 

 for the magnum, which is nearly plane ; behind and slightly 

 internal to it is the concave facet for the trapezoid, and on the 

 postero-internal angle a minute facet for the trapezium. There 

 is no posterior facet for the head of the magnum. The scaphoid 

 of Anchitherium is very similar to that of Mesohippus, but is 

 relatively lower and broader and more cubical in shape, and the 

 trapezoid facet more entirely posterior to that for the magnum. 

 Both of these features are exaggerated in the horse, and the 

 palmar face of the scaphoid much widened and inflected towards 

 the ulnar side. Usually there is no facet for the trapezium in 

 Equus, but according to Kowalevsky it very often is present 

 (No. 25, p. 20). 



The lunar is high and narrow, with the proximal end consider- 

 ably broader than the distal. The radial facet is slightly convex 

 in front, concave behind, and on the internal side descends some- 

 what upon the anterior face of the bone. The lunar is in contact 

 with the scaphoid only at the superior and inferior borders, being 

 elsewhere separated by a considerable interval, but it is closely 

 applied to the cuneiform throughout. The distal end, when 

 seen from the front, is unevenly divided between the magnum 

 and unciform, the former surface being usually much the wider ; 

 in one specimen the proportion is 1 : ij; in another, the magnum 

 facet is but slightly broader than that for the unciform. The 

 latter facet has a smaller antero-posterior extent than the former, 

 the projection from the palmar side covering only the magnum. 



The cuneiform is very narrow transversely, its principal di- 

 ameter being the antero-posterior, caused by a prominent and 



