344 NOTES ON THE CANIDZ OF THE WHITE RIVER OLIGOCENE, 
The shaft of the radius in Daphenus is slender and has a similar shape to that 
which we find in-the cats, although it is not so much expanded distally; it is thus very 
different from the broad, antero-posteriorly compressed and almost uniform radial shaft 
of the modern dogs. The distal portion of the radius is likewise very feline in appear- 
ance, but is rather lighter and narrower in proportion to the length of the bone ; it is 
convex anteriorly and quite deeply concave posteriorly, with well-marked sulci for the 
extensor tendons upon the dorsal face. The distal facet for the ulna is small and of sub- 
circular shape and forms quite a projection upon the ulnar side; upon the inner side of 
the distal end is a tubercle, which is even more rugose and prominent than in Felis, and 
more distinctly set off from the carpal surface. This carpal facet has a shape like that 
seen in the cats, and is more concaye transversely and narrower in the dorso-palmar 
diameter than in the existing forms of Canide, and its internal border is more prolonged 
distally into a downward projecting flange. 
Had this radius been found isolated, one would hardly have hesitated to refer it to 
one of the Machairodont genera, so completely does it differ from the radius of the modern 
dogs. Fortunately, there is no room for scepticism regarding the reference of this bone 
to Daphenus, for several of the specimens, representing different species, have radii of 
the same type. In this connection, it may be of interest to note that the Eocene creodont 
genus, Miacis, which has a remarkably canine type of dentition, has a very cat-like form 
of radius. 
The wna is hardly less characteristically feline than the radius. In marked con- 
trast to the creodonts, which have a very long olecranon, that of Daphenus is rather 
short ; its antero-posterior diameter is proportionately less than in Felis, or even than in 
Canis, and its postero-superior angle is thickened and rugose, though somewhat less so 
than in either of the modern genera mentioned, which gives its proximal border a 
straighter contour than in them. The tendinal sulcus is wider and deeper than in the 
recent dogs, less so than in the cats. The sigmoid notch is deeply incised, but describes 
a parabolic curve rather than a semicircle; the proximal humeral facet is relatively much 
wider than in Canis, and is continuous with the broad distal internal facet, which is like- 
wise broader than in the existing dogs and is shaped much as in the cats, while the 
external distal facet is nearly or quite obsolete. The radial facet is large, quite deeply 
concave, and continuous or single, while in Canis it is much smaller and is divided by a 
sulcus into two portions. 
The shaft of the ulna is stout and, in the proximal portion, laterally compressed, 
tapering toward the distal end, where it becomes trihedral in section. In shape this 
shaft is very much like that of the cats and differs entirely from the ulnar shaft of the 
recent Camda, which has become very much more slender, reduced and styliform, a 
