EDENTATA OF THE SANTA CRUZ BEDS. 51 



The clavicle is unusually well developed and is long, stout and simply 

 curved, somewhat enlarged at the extremities, especially the scapular end. 



The humerus (Plate XIV, fig. i) is of the usual armadillo type, but 

 differs in some respects from that of any recent genus. The head is 

 relatively broader and more prominent than in Priodontes ; the external 

 tuberosity is much larger than the internal, which articulates extensively 

 with the acromion ; the bicipital groove is much narrower than in Dasypus 

 or Priodontes and is brought so far to the inner side as hardly to be 

 visible when the bone is seen from the front. The shaft is heavy and, for 

 most of its length, much compressed laterally ; the broad distal portion 

 is unusually concave on the posterior side ; the deltoid ridge is very 

 prominent and ends in a large, overhanging hook, which is much larger 

 than in the recent genera ; the supinator ridge, though very prominent, 

 is less developed than in Priodontes ; the internal epicondyle is massive 

 and the foramen conspicuous. The trochlea is broad and low, resembling 

 that of Dasypus and Priodontes, except that the convexity for the head of 

 the radius is less hemispherical. 



Ulna and radius (Plate XIV, figs. 2, 3) are in contact only at the ends, 

 thus forming a well-defined radio-cubital arcade. The former is nearly 

 as long as the humerus, which is principally due to the great length of 

 the olecranon ; this process is compressed and plate-like, but with broad 

 and heavy posterior border and deep channels on both sides ; the prox- 

 imal end is broadened, terminating in a large, incurved hook, which is 

 larger than in any other known armadillo ; the sigmoid notch is quite 

 deep, but relatively narrow. The shaft is nearly straight and laterally 

 compressed, but very thick antero-posteriorly, with somewhat broader 

 distal end. 



The radius is very short and has a transversely expanded head, with 

 more simply concave facet than in Dasypus. The proximal portion of the 

 shaft is quite slender, but it gradually thickens (in the antero-posterior 

 dimension) toward the distal end, and is somewhat arched forward. The 

 distal end is suddenly broadened and has quite distinctly separate facets 

 for the scaphoid and lunar ; the styloid process is prominent, but not so 

 elongate as in Priodontes. 



The manus (Plate XIV, fig. 4) is pentadactyl and of the Dasypus type, 

 showing no tendency to the peculiar modifications seen in Cabassous and 

 Priodontes. The carpus resembles that of Dasypus almost exactly. The 



