228 PATAGONIAN EXPEDITIONS! PALEONTOLOGY. 



of the glenoid cavity and, proximal to this cavity, expanding into a broad 

 plate, which is suturally connected with the blade of the scapula and 

 eventually fuses with it, while a shorter and more rod-like process coal- 

 esces with the acromion. The coracoscapular foramen is quite small and 

 of subcircular shape. 



The clavicle is rather slender and is more curved than in Mega /onyx, 

 less than in Megatherium or Mylodon ; this curvature is single and pre- 

 sents the convexity forward ; the sternal end is moderately expanded. 



The humerus (Plate XLI, fig. 4) is very like that of H. longiceps, but 

 much smaller and lighter ; the proximal end is shaped much as in Mega- 

 lonyx, though the tuberosities are more widely and distinctly separated 

 and their proportions are reversed, the inner one exceeding the outer in 

 size ; the bicipital groove is broad and shallow ; the deltoid area is rela- 

 tively somewhat narrower than in H. longiceps and has less elevated 

 borders. The distal trochlea is proportionately narrower than in the latter 

 species and the radial part of the trochlea is relatively larger and more 

 hemispherical, while the ulnar facet is narrower and has a less prominent 

 inner flange. Otherwise, the distal end is almost exactly as in H. 

 longiceps. 



Except for their smaller size and somewhat more slender proportions, 

 the ulna and radius are so like those of the larger species as to require 

 no extended description. 



Very little of the manus is preserved in association with any of the 

 specimens and the few parts that are known differ only in size from the 

 corresponding parts of H. longiceps. 



MEASUREMENTS. 



No. No. No. No. 



15,545- 15,160. 15,597- I5,i55- 



Scapula, length of blade .101 



" greatest width of blade .082 



" width of glenoid cavity .019 



Humerus, length 151 .152 



" width of proximal end 040 .040 



" " " distal trochlea 028 .030 



" " " " end over epicondyles ... .060 



Radius, width of proximal end 019 .018 



" " distal end '. .023 .021 



Ulna, length . 1 56 



" " of olecranon 025 .026 .025 



