54 PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



fourth, its proximal trochlea resembling the corresponding surface in digit II, 

 while in digit IV it is very peculiar, having two prominent convexities, 

 which fit into depressions on the end of metacarpal IV. In digit V the 

 first phalanx is so short as to be hardly more than a broad disc. It is 

 thus apparent that the proximal phalanx is successively shortened in each 

 digit from I to V, with an abrupt change between II and III. 



The second phalanx is most slender and elongate in digit II, in which 

 it is slightly longer and much more slender than the first phalanx, but 

 otherwise like it in shape. In digit III the second phalanx is much shorter 

 (though longer than the proximal one), very much broader and more de- 

 pressed, while in digit IV it is narrower and less depressed than in III. 

 In digit V it is of a different shape, contracting more toward the distal end. 



The ungual phalanges are not unlike those of Dasypus, but are heavier, 

 less decurved and have smaller subungual processes. In the different 

 digits the unguals differ little save in size ; the largest is that of digit III ; 

 in digit IV it is very little smaller, while that of II is considerably smaller. 

 Next in order comes the ungual of digit V, and that of digit I is very much 

 the smallest of the entire series. The distal end of each ungual is cleft by 

 a very short and shallow sulcus. 



MEASUREMENTS. 



Scapula, height 085 Metacarpal II, length 025 



" greatest width 078 " " width of proximal end . . .0065 



" width of neck 027 " " " of distal end 008 



Scapula, antero-posterior diameter of Metacarpal III, length 029 



glenoid cavity 019 " " width of proximal end . . .009 



Humerus, length 093 " " " of distal end oio 



" width of proximal end 024 Metacarpal IV, length 017 



" " of distal end 033 " " width of proximal end .. .010 



Ulna, length 099 " " " of distal end oio 



" " of olecranon 041 Metacarpal V, length 008 



" width of olecranon at proximal end .017 " " width of proximal end.. .005 



" of distal end 014 " of distal end 009 



Radius, length 060 Proximal phalanx, digit I, length 018 



" width of proximal end 016 Proximal phalanx, digit I, width of prox- 



" " of distal end 017 imal end 006 



Carpus, length (proximo-distal) 013 Proximal phalanx, digit II, length 015 



" width 032 Proximal phalanx, digit II, width of 



Metacarpal I, length 013 proximal end 008 



" width of proximal end. . . .007 Proximal phalanx, digit III, length 008 



" of distal end 005 



