376 NOTES ON THE CANID.E OF THE WHITE E.IVEE OLIGOCENE. 



The atlas (PI. XIX, Fig. 13) is somewhat more canine in character than that of 

 Daphcenus, having a short and broad body and moderately developed transverse pro- 

 cesses. The anterior cotyles are shallower and more depressed than in Cams ; 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 Cards 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 vertebra rterial canal presents backward, as it does in Daphcenus, 

 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 Canidce. 



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 

 Daphcenus. 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 convex 

 than in that genus. The odontoid process is slender and elongate, more so than in 

 I iverra, and the articular surface on its ventral side is not, as in Canis, continuous with 

 the lateral facets for the atlas, hut 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 dugs. The neural spine, at least in the White River species, resembles 

 thai of Daphcenus 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 Daphcenus; as in the modern 

 genus, the dorsal border of the .-[line 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, PI. 

 LXXa, Fig. 12), differs from that of C. gregarius in having a much higher neural spine, 

 which is continued posteriorly into a pointed projection, similar to but shorter than that 

 seen in Daphcenus. 



