410 NOTES ON THE CANIDH OF THE WHITE RIVER OLIGOCENE. 
It is exceedingly difficult to unravel all this complicated mesh-work of similarities 
and definitely to distinguish those characters which are due to genetic relationship from 
those which are merely phenomena of parallelism or convergence. But the important 
fact remains that in the late Eocene and early Oligocene all of the families of fissipede 
Carnivora which had then come into existence were very much alike and in all parts of 
their structure resembled one another much more closely than do their modern repre- 
sentatives. They are obyiously converging back to a common term, and the only ques- 
tion is what that common term was and whether we are to look for it in the middle or 
the lower Eocene. It must be reiterated, however, that natural and probable as this con- 
clusion appears to be, it is only tentative and cannot be demonstrated until the successive 
phylogenetic stages of each family are much better known than they are at present. 
SUMMARY. 
1. Daphenus, so named in 1853 by Leidy and afterwards referred to Amphicyon, is 
very different from the latter and an entirely distinct genus. 
2. The dental formula is: I 3, C41, P 4, M3; the premolars are small and sim- 
ple and are set well apart in the jaws; the sectorials are small and primitive, especially 
in ? D. Dodgei, and the molars relatively large, most so in D. vetus. ‘The dentition is 
more like that of the creodont family Iacide than of the typical modern dogs. 
3. The skull is of a very primitive character, with short face, very elongate cranium 
and high sagittal crest; the cranial cavity is of small capacity and the postorbital con- 
striction is placed far back of the eyes. Large frontal sinuses are present. 
4. The occiput is low and broad, with very prominent crest; the paroccipital pro- 
cesses are short and blunt and are widely separated from the tympanic bull. 
5. The auditory bulla is minute and does not fill up the fossa, exposing the periotic ; 
it probably represents only the anterior chamber, the posterior chamber was either not 
ossified or was very loosely attached, so that it is lost in all the known specimens. 
6. The cranial foramina differ very little from those of Canis. 
7. The mandible has a short horizontal ramus, varying in its proportions in the 
different species ; the ascending ramus is low and very broad. 
8. The brain is remarkable for the small size and simple convolutions of the cerebral 
hemispheres and the large size of the cerebellum and olfactory lobes. 
9. The foramina of the atlas differ from those of: the recent dogs and resemble those 
of the cats. 
10. The axis is also of feline character, especially in the shape of the neural spine. 
11. The other cervical vertebrxe have more prominent zygapophyses, narrower neu- 
ral arches and higher neural spines than in Canis, 
