1922J Kellogg: Pinnipeds from Miocene and Pleistocene Deposits 37 



two deep pits in this area, two of which are just below the plantar 

 border of the scaphoid facet. 



Measurements of Trapezium 



Greatest transverse diameter 46. mm. 



Greatest dorsoplantar diameter 36.8 mm. 



Greatest distoproximal diameter 44. mm. 



The second metacarpal (fig. 12a) resembles the fourth metacarpal 

 (figs. 12&, 12c) in the general contour of the distal and the proximal 

 articulating surfaces. The facet for the trapezoid is strongly convex, 

 running over upon the dorsal face of the shaft and extending back- 

 ward to the plantar border. The transverse width of this facet across 

 the dorsal face is much wider than that of the fourth metacarpal. No 

 trace of a groove for the radial artery seems to be present, though there 

 is a rugose area for the possible insertion of the extensor muscles. 

 The lateral ulnar face is strongly expanded distal ly and narrows 

 rather abruptly proximally. Ulnar and radial tubercles but slightly 

 developed. The head and the upper end of the shaft present a number 

 of points of difference when compared with Eumctopias stelleri; for 

 instance, the articular facet for the trapezoid is strongly convex while 

 in the latter it is decidedly flattened. 



Measurements of Metacarpal II 



Greatest length 101.4 mm. 



Transverse diameter of proximal end 25.3 mm. 



Narrowest transverse diameter of shaft 17.9 mm. 



Transverse diameter of shaft at distal end 30. mm. 



Anteroposterior diameter of shaft at distal end 16.4 mm. 



The bone determined as the fourth metacarpal (figs. 12&, 12c) of 

 the right fore limb is the lightest of the three metacarpals at hand. 

 The proximal end is characterized by the fact that the facet for articu- 

 lation with the unciform is strongly convex and not concave as in the 

 carnivores. This suggests the conclusion that the carpal bones allowed 

 these metacarpals much more freedom of movement, which in turn 

 indicates that, this form had apparently progressed very little toward 

 that highly specialized flipper which is so characteristic of the pinni- 

 peds. On the lateral ulnar face of the base there is a conspicuous 

 tuberosity for articulation with the third metacarpal. The dorsal 

 surface of the shaft is rather evenly convex. Ulnar and radial 

 tubercles of the head are slightly developed. The articular surface 

 of the head for articulation with the proximal digit is more flattened 

 and exhibits a lesser degree of convexity than that of the base. Dis- 



