coming very high, rugose and thick. 
THE OSTEOLOGY OF HYiENODON. 
not very thick, hut of great vertical diameter; toward the free end i 
it expands, be- 
517 
occui.ied by the large facet for Hie scaphoid, which is quite convex transversely, and 
descends low upon the radial side of the trapezium. On the external or ulnar side 
are^ two tiicet.s, obscurely separated by a faint ridge. Of these the proximal one, 
which is the larger and more concave, articulates with the trapezoid ; the distal one 
is r.-shaped and articulates with the head of the second metacarpal. On the distal 
side of the trapezium is a large, oval and concave facet for the head of the first 
metacarpal ; this facet presents obliquely downward and inward and indicates an 
unusual freedom of movement, perhaps even some degree of opposability, on the 
part of the first digit. 
The /rapezoid \s, a rather small bone, though relatively somewhat larger than 
in the dogs. Its largest area is the dorsal face, from wdiich it tapers to the palmar 
side, where it terminates in a blunt point. The proximal surface is unequally 
divided between the facets for the scaphoid and central; the former is small, of 
triangular shape and slightly convex, the latter much larger and concave. On the 
radial side is a large facet for the trapezium, but the trapezoid does not extend to 
nearly so low a level as does the latter. On the distal side is a saddle-shaped sur- 
face for the second metacarpal, which is convex transversely and less decidedly con- 
cave in the antero-])osterior direction. 
The viagnutn is not preserved in any of the specimens, but its shape and con- 
nections may be confidently inferred from the facets of the surrounding bones. It 
had no articulation with the scaphoid and was connected proximally only with the 
lunar and central, more extensively with the former than with the latter. Later- 
ally it articulated with the trapezoid and unciform, distally with the third meta- 
carjial and by a very small facet with the second. In size the magnum must have 
Lofiii <»f’ file siTinllest bones in the carpus. 
