Temnbcyon and Ilypotemnodon. — Eyerman. 273 
The hypoconid is equally well developed in both, but in the 
type has a sharp elongated surface, which in ferox, is pointed 
toward the centre giving rise to a pyramidal structure. The 
groove between this cone and the protoconid is deeper in the 
type. The protoconid is separated from the para- and hypo- 
coni ds by a well defined groove. The height of this cone is 
15 mm., and in the type 11 mm. In T.. ferox the metaconid 
rises from the side of the protoconid, but in the type species 
from the base thereof. On account of the irregular contour 
of the crown of this tooth in the type species the posterior cone 
is in a direct line drawn through the paraconid, while in 77 
ferox , which has a regular parallellogram-shaped crown, the 
hypoconid is directly posterior to the former. There is a min¬ 
ute entoconid at the posterior edge, which is, however, absent 
in the type species. 
The antero-posterior diameter.of m72 is nearly equal in both 
species and the transverse only one-fourth greater in T.ferox r 
the height of the protoconid is very little greater and the apex 
thereof is less acutely pointed and hence the diameter of the 
base is greater in this species; the hypoconid has the same 
height in both species and, like the protoconid, is more acute 
in the type; the internal cusps are absent in both. A cingu¬ 
lum is developed in T.ferox , but in the type is very rudimen¬ 
tary, if developed at all. 
The Vertebral Column .—The axis (fig. 5) is longer and more 
robust, and the odontoid process somewhat shorter than in the 
living species. The diameter of the concavity above the articu¬ 
lar surface for the atlas is slightly greater and not so sharply 
curved, and the transverse diameter is greater at the posterior ; 
the lower part of this surface does not project below the lower 
line of the bone, the transverse processes and the zygapophyses 
are stronger and of greater width ; the vertebrarterial foramen 
is placed nearly at the base and is more elongated. The first 
thoracic vertebra measures 34 mm. across the anterior and 
36 mm. across the posterior zygapophyses. The lumbar verte¬ 
brae differ somewhat from the usual shape found in recent 
Canidce; the antero-posterior diameter of the first lumbar 
being somewhat greater than the transverse, but in the seventh 
the former diameter is one-half that of the latter; the trans¬ 
verse processes are here unusually robust, but they do not 
