PETERSON: A REVISION OF THE ENTELODONTIDA Hel, 
Lunar. —The lunar of Dinohyus is distinctly more modified than. is the case 
in Entelodon and Archeotherium. In Dinohyus the vertical and antero-posterior 
diameters in relation to the transverse, are greater than in the Princeton specimen, 
a character naturally to be looked for in a later form. As in Archzxotheriwm, the 
facet for the radius is divided into two parts, an anterior and a posterior ; the 
former has a less abruptly rounded transverse ridge than in Archwxotherium, and the 
latter has a relatively greater antero-posterior diameter and is deflected on the ulnar 
side to a greater degree. The dorsal face has a slightly dif- 
ferent outline from that figured by Kowaleysky (38, PI. 
XXVI, figs. 21-32), and also different from that which ap- 
pears in the Princeton specimen. The principal difference in 
outline from that of the older forms is caused by the conyex 
facet for the magnum on the radial face. In A rchexothervum 
the facet is altogether the reverse, being concave instead of 
In Dinohyus it is seen that both the 
A + 
Vy 
i * (" 
convex (see fig. 71). \" | 
magnum and the unciform have yielded to the development ! I 
and modification of the beak of the lunar so that the lateral 
contact of the two is entirely lost dorsally, and the lower end 
of the lunar isalmost in touch with the proximal end of the 
third metacarpal (see fig. 70, 2). The beak which is more 
bluntly pointed than in Archzotheriwm is also apparently 
shifted farther toward the radial side than in the latter genus. 
The palmar face has a more oblique outline above ; other- 
wise it is quite similar to that of the Oligocene genus. The 
ulnar side has two facets for the cuneiform, which are almost 
identical with those of Archwotherium. The dorso-proximal 
facet for the scaphoid is more clearly defined than in Arche- 
otherium and the changed condition of the dorsal facet for the 
magnum, as stated above, gives to the radial face of the bone 
a more nearly vertical position than in the latter genus. The 
Fie. 71. 
Portion of Fore Foot of Archx- 
Anterior View of 
otherium crassum Marsh. 4 nat. 
(Carn. Mus. Cat. Vert. 
Foss., No. 1665.) 
size. 
posterior portion of the facet for the magnum is recurved downward and developed 
into a hook on the 
Princeton specimen. 
MEASUREMENTS. 
Lunar, greatest antero-posterior Giameter.........eceeeeeeeeeeeeeeeeee ees 
ws ae transverse cS ANUOLIOMI Vers sse tower sey Bere 
WG oe rs ‘posteriorly... 
Us es vertical ‘© anteriorly 
« « « ce 
posteriorly... 
posterior radial angle, which is relatively larger than in the 
Mm. 
Ae err 60 
atte OTA 45 
