MEGACEROPS TYLERI 453 



Of the distal row of carpals the trapezoid is absent, having been 

 replaced in the mount by that from another individual. It is not a 

 precise fit, there being some variation between its facets and those 

 of the original bone. 



The articular faces are well shown in the figure, and it will be 

 noted that lateral movement is impossible, while a remarkable range 

 of flexion is indicated. 



The magnum has on its lower face facets for the articulation of 

 meta-carpals 2 and 3, that for 2 being rectangular, about four times 

 as long as wide. The pivot of the magnum is high and prominent, as 

 indicated in the figure. 



The unciform is the largest bone in the carpus, with the possible 

 exception of the lunar. Distally it bears two facets for metacarpals 4 

 and 5, while on the radial side there is one which articulates both 

 with the magnum and with metacarpal 3, the limits of the two articu- 

 lations not being discernible. 



A study of the distal carpal facets and the proximal metacarpal 

 ones gives evidence again of more or less fore and aft movement, but 

 in the case of the median metacarpals no lateral movement at all. 

 The lateral metacarpals, on the contrary, were capable of lateral as 

 well as fore and aft movement, so that, while the foot would spread 

 somewhat when the creature's weight was borne upon it, it was all 

 in the lateral bones. This would seem to be still further evidence 

 that the true axis of the foot was between digits 3 and 4, as in the 

 artiodactyls. 



The principal dimensions of the manus are: 



Width of proximal facets 0.170 



Width of distal carpals - - - - - - -.170 



Depth, lunar to summit of metacarpal 3 - - - .080 



Length of metacarpal 3 ------- .250 



THE HIND LIMB 



The entire limb is figured in Plate IV, Fig. 4. There was no trace 

 of the pelvis found associated with No. 327, though the limbs are in 

 excellent preservation and give but little evidence of distortion by 

 crushing. 



The femur. — This is a fine bone, notable for its extreme flatness, 

 which indicates the pillar-like posture of the bone, as in the elephant, 



