348 



NOTES ON THE CANTON OF THE WHITE EIVER OLIGOCENE. 



that of me. ii and is of a more quadrate section, the dorsal and lateral surfaces forming- 

 distinct angles. 



The fourth metacarpal has a narrow, hut deep head, which projects prominently 

 behind the plane of the shaft ; the facet for the unciform is slightly concave in the 

 transverse and strongly convex in the dorso-palmar direction. Compared with the cor- 

 responding bone of Canis, the following differences in the shape of the facets for the 

 adjoining metacarpals may be observed. The surface for mc. iii is, as in the recent 

 animals, divided into dorsal and palmar portions, but they are not completely separated ; 

 the dorsal moiety is much larger, but not nearly so prominent, and the palmar portion is 

 much smaller. The facet for mc. v is of about the same sha])e in both genera. The 

 shaft is slender and nearly straight, but slightly arched toward the dorsal side ; though 

 relatively short, it considerably exceeds mc. ii in length. The prominence of the lateral 

 ligamentous processes gives great proportionate breadth to the distal end. The trochlea 

 is like that of mc. ii, except for its greater size and presents the same differences from the 

 modern type. 



The fifth metacarpal has been lost from the specimen. 



The phalanges are very remarkable, but can be most conveniently described in con- 

 nection with the pes, with which the most complete specimens are associated. 



Measurements. 



No. 11425. 



Scapho-lunar, breadth 



" " depth (dorso-palmar) 



Metacarpal i, length , 



" breadth of proximal end.... 



" distal end 



" distal trochlea... 



Metacarpal ii, length 



" breadth of proximal end.. 



" " distal end 



" " trochlea.. 

 Metacarpal iii, breadth of proximal end. 



Metacarpal iv, length 



' breadth of proximal end.. 



" " distal end 



" " " trochlea. 



.026 

 .009 



