EDENTATA OF THE SANTA CRUZ BEDS. 29 



becomes convex, curving gradually into the suprascapular border, while in 

 both of the last-named genera the two borders meet at an angle. So far 

 as it is preserved, the suprascapular border is regularly arched, but, as the 

 postero-superior angle of the blade is broken away, I cannot determine 

 whether or not it had the remarkable prolongation seen in most recent 

 armadillos. It may be inferred, however, that the angle was much less 

 produced in the fossil, because the glenoid border is nearly straight, not 

 concave ; this border is thickened and forms a ridge, which is roughly 

 parallel with the spine and, while rather more conspicuous than in Tatu, 

 is much less so than in most other modern genera. The spine is placed 

 slightly behind the middle of the blade, making the prescapular fossa a little 

 larger than the postscapular ; it is high and very strongly recurved, so as 

 to have a deeply concave posterior side. The acromion is broad, thin and 

 curved forward ; so far as it is preserved, it resembles that of Tatu, except 

 in having a smaller metacromion, but it is so broken that its length is in- 

 determinable. The glenoid cavity is shallow, narrow transversely, but 

 quite elongate, and the coracoid is small. 



The humerus (Plate IV, fig. 4) exhibits some peculiarities ; the head is 

 elongate, narrow and quite strongly convex in both directions, projecting 

 somewhat behind the plane of the shaft ; the external tuberosity, though 

 broken, was evidently very large, while the internal one is greatly reduced, 

 as in Tatu, bringing the bicipital groove, which is narrower than in the 

 latter genus, to the inner angle of the proximal end. The deltoid area, 

 though larger and more prominent than in Tatu or Dasypus, is not so 

 well developed as in the other Santa Cruz genera ; it is broad and rugose 

 with prominent borders, which give a concave shape to the sides of the 

 shaft. The latter is short and heavy and of the usual shape, compressed 

 and thick proximally, broad and thin distally ; the supinator ridge is very 

 prominent, adding much to the breadth of the distal part and its outer 

 border passes upward into a raised line, which extends on the hinder face 

 of the shaft to the inner tuberosity ; the internal epicondyle is very large 

 and massive and the foramen is also large. The trochlea is quite different 

 from that of Tatu or Dasypus, being broad and low, but increasing in 

 vertical diameter towards the inner side and ending on that side in an 

 unusually prominent sharp-edged flange, which is highly characteristic ; 

 the tuberosity for the head of the radius is much more convex and distinct 

 than in the other Santa Cruz genera and shifted nearer to the median line. 



