PETERSON : A REVISION OF THE ENTELODONTID © 119 
carpus and ulna (Palaeontographica, Vol. XXII, Pl. XI, fig. 58). In Sus the 
pisiform is shorter, thinner, and deeper, while in Hippopotamus it has a general 
similarity to the pisiform of the Mntelodontide. 
MEASUREMENTS. 
Mm. 
Pisiform, greatest length ..............10.cseesesedccsrceescecnascersssecsocsesoaseesasesteneees 70 
ue Vertical-diameber,or Proximal) CNUs. sc..re.. eset ces rse Voces ep aceans 82 
ff transverse ‘‘ ee Be Ly 
“ iss ce e distal “et ea 
Ka vertical Gd YG be ies 
Trapezium. —The trapezium of Dinohyus is no doubt entirely wanting, judg- 
ing from its rudimentary condition in the Oligocene genus,* and its entire absence 
in the John Day form. Professor Cope states (10, pp. 62-63) that there is no trace 
of a facet for a trapezium on the trapezoid of Bodchawrus hwmerosus, which was veri- 
fied by me on examination of the type specimen in the American Museum.* 
Trapezoid. —' Though absent in the type of Dinohyus this bone was found in posi- 
tion on the magnum of a fore foot, found in section 19 (see plan of quarry, Pl. LIV, 
No. 47) and is here described. 
The transverse diameter of the trapezoid (No. 2136, Carn. Mus. Cat. Vert. Foss.) 
is only two millimeters greater than in Archwotherium, while the antero-posterior 
diameter is proportionately somewhat greater. The bone is consequently much com- 
pressed laterally and has a subquadrate outline, when viewed from its ulnar face. 
Radially the proximal face is more rounded before backward, by the articulating sur- 
face for the scaphoid, which gives this (radial) face a more irregular quadrate appear- 
ance. The transverse diameter of the bone is greatest proximally, and it gradually 
tapers distally, terminating in a border, whichis rather narrow and rounded inferiorly. 
The facet for the scaphoid is obliquely convex antero-posteriorly and extends well 
back on the posterior face of the bone. The ulnar face bears three facets for the mag- 
num, two of which are distal and one proximal. The proximal facet is well defined 
near the dorsal face and continues backward as a smooth rounded ridge on the proxi- 
mo-ulnar angle. The two distal facets are a palmar and a dorsal, and may be regarded 
as practically one facet, as they are divided only by a very shallow, almost imper- 
ceptible, groove, while in Archxotheriwm there is a moderately large median swelling 
on the ulnar face which puts the two facets at a considerable angle with each other. 
‘8 There is, in the Princeton specimen described by Professor Scott, a trapezium with a well formed facet for the 
trapezoid, and the bone, though laterally compressed, is of considerable size antero-posteriorly and extends well down 
over Me. II, but does not articulate with the latter. (See fig. 10 on page 55.) 
“Tn my note book I find the following statement regarding the trapezium of Bodchwrus: “ The trapezoid has a 
small pit radially which may have lodged a trapezium, but there is no distinct facet.” 
