EDENTATA OF THE SANTA CRUZ BEDS. 83 



glenoid border. The coracoid differs from that of Prozaedius in being 

 shorter, broader and bifid at the end. 



The humerus (Plate VI, fig. 21) differs from that of Zaedyus and Pro- 

 zaedius in only a few respects ; the head is longer, narrower and more con- 

 vex, the tuberosities are more widely separated and the bicipital groove is 

 open, not a canal ; the shaft is longer and more slender and the deltoid 

 ridge does not project so much externally ; on the trochlea, the groove ex- 

 ternal to the convexity for the head of the radius is deeper and its outer 

 flange more prominent. 



The ulna (Plate VI, fig. 22) is very like that of Prozaedius, but is dis- 

 tinguished not only by its larger size, but also by its more pronounced 

 sigmoid curvature, the greater breadth of the anterior border of the ole- 

 cranon, the greater length and less breadth of the sigmoid notch, the thin 

 plate-like character of the shaft and the slight expansion of the distal end. 



The radius (Plate VI, fig. 23) has a broader head than in the preceding 

 genus and the articular surface is more distinctly divided into two facets, 

 of which the external is much larger ; the distal end is quite the same, 

 except that the division between the two carpal facets is much less dis- 

 tinct ; the proximal portion of the shaft is extremely slender. 



The manus (Plate VI, fig. 24) displays some of the most characteristic 

 features of the present genus. In most respects, the carpus is like that 

 of Dasypus, but it has certain peculiarities. The proximal portion of the 

 scaphoid is much extended palmo-dorsally and projects out above the 

 trapezoid in a great, spur-like process. The lunar has a more strongly 

 convex surface for the radius, which is reflected farther upon the dorsal 

 side than that of Prozaedius. In the pyramidal the only noteworthy dif- 

 ference from the latter genus is in the shape of the ulnar facet, which 

 has not the deep concavity near the external end. The pisiform resembles 

 that of Dasypus, but is more elongate, slender, incurved and tapering. 

 The trapezium is not known and the trapezoid requires no description, 

 except to mention its somewhat unusually extensive articulation with 

 metacarpal III, while the magnum is relatively much larger than in Pro- 

 zaeditis. The unciform is quite as in the latter, but is somewhat longer 

 in proportion to its breadth, and its distal face is more deeply notched for 

 the narrow, convex head of metacarpal IV. 



The metacarpus consisted of five members, though metacarpal I has 

 not yet been found. Metacarpal II is elongate and quite slender and its 



