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 UINTA SELENODONTS 



37 



atively larger than in the White River genus. Though rac. ii. appears to have 

 no contact with the magnum, mc. iii. does not reach the trapezoid. The pres- 

 ent genus, apparently, and certainly its White River successor, are thus in a 

 stage of transition between the modes of reduction which Kowalevsky has 

 named the "adaptive" and the " inadaptive;" inc. ii. is cut off from its con- 

 nection with the magnum, but mc. iii. has not yet acquired any articulation 

 with the trapezoid. The shaft of mc. iii. is straight and relatively broad, but 

 much compressed antero-posteriorly and of transversely oval section, though 

 flattened on the ulnar side by the approximation to mc. iv. Distally the two 

 are slightly separated, but with no marked appearance of that divergence 

 which is so characteristic of the later Camelida;. 



Metacarpal iv. is the counterpart of mc. iii., but is a little shorter, the 

 head not rising so high as that of the latter, though this difference is compen- 

 sated for by the height of the unciform, which descends below the level of 

 the magnum ; the shaft is also a little broader proximally and more flattened 

 on the dorsal face ; the head is narrow, no wider than the shaft. 



Metacarpal v. is the counterpart of mc. ii., with which it forms a symmet- 

 rical pair. The proximal end is very narrow, though it bears a small tubercle 

 for ligamentous attachment on the ulnar side; the shaft is slightly curved, 

 with the convexity towards the radial side, while that of mc. ii. is unusually 

 straight and stiff looking. 



MEASUREMENTS. 

 Scapula, breadth of neck ..... 



anteroposterior diameter of glenoid cavity 

 Humerus, antero-posterior diameter of shaft, proximal 

 breadth of trochlea .... 

 height of trochlea .... 

 Ulna, length of olecranon .... 



Metacarpal ii., breadth of proximal end 



" iii., " " .... _ 



o.oio 

 .0095 

 .014 

 .0095 

 .00S 

 .013 

 .003 

 .006 

 .005 

 .004 



V. The Hind-Limb is proportionately long and robust, much more 

 so than the fore-limb. The pelvis is as characteristically tylopodan as the 

 other parts of the skeleton, and, so far as the material admits of a com- 

 parison, it much resembles that of Pocbrotlierium. The ilium is short, but 

 has a relatively elongate peduncle, which is deep dorso-ventrally and, though 



