524 
THE OSTEOLOGY OF HYxENODON. 
Tl,e tx. is sl,ort. decidedly shorter than the femur, and in gener.al character 
most n-seinbles that of such recent plantigrade genera as Procyott. The condj es 
are rather small, nearly plane transversely and slightly convex antero-posteriorly 
The posteroexternal angle of the outer condyle forms a broad, overhanging shelf, 
on the distal surface of which is a large, plane facet for the head of the fibula. The 
cnemial crest is only moderately developed and is much less prominent than m the 
CixnidiC ; it extends, however, quite far down the anterior face of the shaft. The 
proximal portion of the shaft is quite heavy and of trihedral section ; it has a double 
curvature, like that of the femur, arching forward and toward the mesial side; the 
distal portion of the shaft, on the other hand, is of rounded form and nearly straight. 
The distal end is but moderately widened and thickened and has nearly equal 
transverse and autero-posterior diameters. The articular surface for the astragalus 
is quite w.ell grooved and distinctly divided into two facets, the inner one of which 
is nari'ow and deep, the outer one broad, but slightly concave and placed at a very 
acute angle with the long axis of the shaft. Except at the anterior margin, the 
intercondylar ridge is low and inconspicuous. This ridge is better developed in 
H. horridus than in the smaller species and the astragalar facets are more deejily 
impressed. In all the species the malleolar process is prominent and thick antero- 
posteriorly, though not very long; its distal end bears a facet for a pit on the neck 
of the astragalus, a character which is very common in the creodonts. The distal 
fibular surface is not a distinct facet, but merely a groove on the outer side of the 
tibia. 
T\\<i fibula is relatively little reduced, even less so than in the Procyonidc?, except 
in H. crucians, in which, according to Wortman (No. 4, p. 225) it is very slender. 
Ihe proximal end is very heavy and is expanded both in 
breadth and thickness ; it articulates by a large, plane facet 
with the lower side of the overhanging external condyle of 
the tibia, which has been already described, and on its outer 
face IS a deep tendinal sulcus. Somewhat below this enlarged 
a..d most contmeted, but it stx... 
aud libula of young and gradually, though not regularly, increases in 
animal, natural «ize. diameter toward the distal end. The double curvature of the 
t.bia produces a wide interval between the two le-boncs 
whether seen from the front or the side, and though the shaft of the fibula i:neari; 
Jir 1;:^ 
1 1 • I t, X. fiighly characteristic of the o-enus It is 
enlarged m both the transverse and antem r x “ 
latto,-; on the outer side is a broml „d , r • !"" espocially i„ the 
which forms a tendinal groove- on the imTer^'^!l ’ process, 
ex, face, for the extcrual WUm !" 
lie calcaneum. Tlie ntilpono.,! r„„„x x, ^ distal side is a facet 
for the calcaneum. The calcaneul fnoot , «u uie aistal side is a facet 
neea (fore-ai.d-aft) „f the Kbular'ead No e'oetiM™’ ““‘’1''* 
sive and elaborate articulation between the'k.d, 7°"; 
Hy^noden. nor I, it found in „tber known creod„.“ 
