42 



TEETIAET VEETEBEATA OF THE EATtM. 



the upper edge of the lunar. The distal end is occupied by a greatly elongated 

 articular surface (tz.), slightly convex in all directions, which probably articulated with 

 both the trapezium and trapezoid. Anteriorly the outer (postaxial) border of this 

 surface is connected with two other facets, of which the anterior one (IJ) is a flat 

 elongated surface looking outwards and downwards for union with the lower facet of 

 the lunar, while the other (mag.) lying immediately behind the last is triangular in 

 outline, and looks downwards and backwards, and apparently united with the postero- 

 internal angle of the upper surface of the magnum, as is the case in Elephas. Both the 

 outer and inner faces of the bone, where not occupied by articular facets, are greatly 

 roughened and pitted. 



The form of scaphoid here described and figured is definitely known to be that 



Text-fig. 21. 



ma^. 



Eight lunar of Arsinoitlierium zitteli: A, from above; B, from front ; C, scaphoid face. 



mag., facet for magnum ; r., surface for radius ; sc, sc.', upper and lower surfaces for scaphoid • 



tr.'!, facet for trapezoid ; u., surface for ulna. § nat. size. 



of Arsinoitherium, but at the same time it is very like that of Elephas, and its 

 relations to the neighbouring bones, so far as determinable, are similar. This scaphoid 

 differs from that of Mephas in the following respects : — (1) its proximal articular 

 surface is concave, owing to the stronger convexity of the portion of the radial head 

 with which it articulates ; (2) the lower surface for the lunar is shorter from before 

 backwards and at the same time deeper ; (3) the distal articulation is much lono-er from 

 before backwards, extending considerably behind the triangular surface for the magnum • 

 the whole distal end of the bone is, in fact, much more expanded than in Elephas. 

 - The lunar (text-fig. 21) here described is presumed to belong to Arsinoitherium 



