ON SOME NEW AND LITTLE KNOWN CREODONTS. 
161 
an external facet for the ulna and two distal concave faces for the scaphoid and lunar. 
In Pachyama the radius is relatively shorter, more flattened, and the facets for 
the scaphoid and lunar are not separated. 
Tlie ulna is slender with a snbtrihedral curved slraft, and long very stout olecran- 
non. The distal end is a narrow convex surface for the cuneiform. In Pachycena 
the ulna is straighter, the olecrannon not so hroad, and the distal end acuminate. 
The carpus (PL VII.) is of extraordinary interest, and is distinctly like that of the 
Insectivora. The scaphoid, which is separate from the lunar, has very little dexAh ; the 
tuberosity is smaller than in the Carnivora ; the surface for the radius narrow and con- 
vex. Distally there are three facets ; (in M. Icmhis those for the trapezium and trape- 
zoid are confluent), a small internal one for the trapezium, a larger median one for the 
trapezoid, and externally a narrow and deeply excavated one, which Professor Cope 
considers to be for the magnum, but which is really for the central. The lunar has a 
very convex upper surface, the radial articulation extending over the front face. The 
distal end is wedge-shaped, formed by two deeply conca^'e facets, a larger one for the 
magnum and a smaller one for the cuneiform. Professor Cope’s restoration of this 
bone (Tertiary Vertebr. PL XXIX, Fig. 3) is much too large and entirely incorrect in 
shape. 
The cuneiform is very unlike that of the Carnivora. The ulnar surface is narrow 
and concave ; posteriorly there is a broad face for the pisiform, which rests against and 
not upon the cuneiform. The uneiform surface is also concave. 
The pisiform is very stout and has a hea \7 knob at the distal end. The ulnar 
facet is reversed D shaped, that for the cuneiform more quadrate in outline, the two 
meeting at an angle of about 45° The trapezium is high and narrow, and has four 
articular surfaces, one small and round for the scaphoid, a larger concave facet joins 
the trapezoid ; beneath is a flat quadrate surface for metacarpal II, and distally is a 
very small saddle-shaped facet for the rudimentary metacarpal I. The trapezoid is a 
stout bone, broader in front than behind. It rises considerably above the level of tlie 
magnum. Its metacarpal is the stoutest of all. 
The magnum is the smallest bone in the carpus, except perhaps the central ; the 
A^ertical diameter is its least dimension, and is much exceeded by the unciform and 
trapezoid. The magnum possesses flve articular surfaces, for the lunar, central, trape- 
zoid, imciform and metacarpals II and III. The upper facets are strongly convex, 
that for the lunar is the larger, that for the central very narroAv. The articulation 
Avith metacarpal II is someAvhat. larger than Avith III. 
The centred. I haA'e spoken confldently of the presence of this element, although 
it is not preserved in any specimen I have yet seen. Its existence is hoAvever made 
A’ery clear by the folloAAdng facts: (1) The scaphoid is prevented from reaching the 
magnum by the height of the trapezoid and by the mode of articulation Avith the lu- 
(2) On the distal face of the scaphoid is a facet Avhich is not occupied by tlie 
nar. 
