EDENTATA OF THE SANTA CRUZ BEDS. 235 



the internal epicondyle and the supinator ridge are very heavy and promi- 

 nent, but the supratrochlear and anconeal fossae are even shallower than 

 in the last named species. 



The ulna is but little longer than that of H. elongatus and considerably 

 stouter; the olecranon is somewhat broader at the free end and the 

 humeral facet is of a rather different shape, being wider and also extend- 

 ing farther up on the external side. The shaft is quite heavy and the 

 strongly convex curvature of the posterior border gives it quite a dif- 

 ferent appearance from that of the preceding species. 



The radius differs very little, except in being heavier, from that of H. 

 elongatus; the broadening of the shaft below the proximal half is some- 

 what greater and more abrupt and on the anterior side of the distal end 

 is a broad and deep sulcus for the extensor tendons ; the carpal facet is 

 unusually concave. 



MEASUREMENTS. . 



Scapula, width 089 Radius, length 137 



" antero-posterior diameter of " width of proximal end 020 



glenoid cavity 029 " " " distal end 026 



Scapula, width of glenoid cavity 022 Metacarpal III, length 033 



Humerus, width of distal trochlea 034 " " proximal width I95 



" " " " end over epi- " " distal width 013 



condyles 065 " " " thickness 0185 



Ulna, length 161 Metacarpal IV, length 038 



" " of olecranon .027 " " proximal width oio 



" width at sigmoid notch 024 " " distal width 012 



" of distal end 013 " " " thickness .015 



The femur differs considerably from that of H. elongatus; the head is 

 larger and rises considerably above the level of the great trochanter, and 

 the pit for the round ligament is extended to the edge of the articular sur- 

 face ; the great trochanter is lower and there is no notch between this 

 process and the head ; the shaft is considerably broader and more com- 

 pressed antero-posteriorly, while the third trochanter and external tuber- 

 osity are more prominent ; the rotular groove is shallower. 



The tibia differs from that of the preceding species only in its length 

 and greater relative stoutness, and the same description applies to the 

 calcaneum and metatarsals III and IV. Compared with H. e/oiigafns, the 

 hind limb exceeds the fore limb more in length. 



