376 NOTES ON THE CANIDZ OF THE WHITE RIVER OLIGOCENE. 
The atlas (Pl. XIX, Fig. 13) is somewhat more canine in character than that of 
Daphenus, haying a short and broad body and moderately developed transverse pro- 
cesses. The anterior cotyles are shallower and more depressed than in Canis ; the neu- 
ral arch is well extended in the antero-posterior direction and is quite smooth, without 
ridges or tubercles of any kind; it is very strongly convex, giving to the neural canal 
an almost circular shape. The inferior arch is very slender and has but a rudimentary 
hypapophysial tubercle. The posterior cotyles for the axis are somewhat more concave 
than in Canis and present more obliquely toward the median line. The transverse pro- 
cesses are rather small and are much less extended antero-posteriorly than in Canis, not 
reaching so far behind the surfaces for the axis, nor so far forward upon the neural arch ; 
in consequence of this, the atlanteo-diapophysial notch is less deeply incised. The pos- 
terior opening of the vertebrarterial canal presents backward, as it does in Daphanus, 
but has shifted a little more toward the dorsal side of the transverse process, thus show- 
ing a tendency to assume the position which is characteristic of the recent Canide. 
The axis is not especially canine in appearance, but rather resembles that of Viverra. 
The centrum is long, narrow and very much depressed anteriorly, becoming somewhat 
deeper vertically toward the hinder end, which has a transversely oval and nearly flat 
face for the third vertebra; the ventral keel is relatively better developed than in 
Daphenus. The articular surfaces for the atlas are low and wide, but project much less 
outside of the pedicels of the neural arch than they do in Canis, and are more conyex 
than in that genus. The odontoid process is slender and elongate, more so than in 
Viverra, and the articular surface on its ventral side is not, as in Canis, continuous with 
the lateral facets for the atlas, but is separated from them by a feebly marked ridge. 
The transverse processes, which are very thin and compressed, are of no great length; 
they are perforated by the vertebrarterial canal, which is relatively longer than in the 
recent dogs. The pedicels of the neural arch are short from before backward, but are 
quite high, and the neural canal is proportionately much larger in both dimensions than 
in the existing dogs. The neural spine, at least in the White River species, resembles 
that of Daphenus much less than it does that of Canis. It is long, not very high, and 
in front extends far in advance of the pedicels, but posteriorly it does not project 
behind the zygapophyses, as it does so conspicuously in Daphenus; as in the modern 
genus, the dorsal border of the spine is continued into the hinder margins of the neural 
arch. The zygapophyses are rather small and do not extend out so prominently from 
the sides of the neural arch as in Canis. 
The axis of the John Day species, C. geismarianus, as figured by Cope (’85, Pl. 
LX Xa, Fig. 12), differs from that of C, gregarwus in haying a much higher neural spine, 
which is continued posteriorly into a pointed projection, similar to but shorter than that 
seen in Daphenus. 
