NOTES ON THE CANID.E OF THE WHITE RIVER OLIGOCENE. 66? 



all three facets are confluent. The neural arch is low and broad, considerably elongated 

 from before backward, and without ridges of any kind, save an inconspicuous tubercle, 

 which represents the neural spine. Near its anterior border the arch is perforated by 

 the usual foramina for the first pair of spinal nerves. The inferior arch is very slender, 

 forming a more curved bar and has a much less antero-posterior extension than in Cards. 



Wortman ('94, p. 137) has pointed out that the foramina of the atlas display certain 

 characteristic features in the various carnivorous families. " In all of the Felidce which 

 I have had the opportunity of studying, the [vertebrarterial] canal pierces the transverse 

 process at its extreme posterior edge, where it is thickened and joins the body of the 

 bone. The superior edge of this posterior border slightly overhangs the inferior edge. 

 .... This character appears to be very constant in the Felidce and so far as we know 

 the structure of the atlas in the more generalized Nimravidce [Machairodonts] , it is true 

 of them also. In the Canidce, upon the other hand, the foramen for the vertebral artery 

 is situated well in advance of the posterior border of the process, and instead of having 

 a fore-and-aft direction, as in the cats, pierces the process almost vertically from above. 

 In the Viverridce and Hycenidce the position of the foramen is very much as in the cats. 

 There is, however, an important difference between these two families and the felines 

 where the artery enters the suboccipital foramen in the anterior part of the atlas. The 

 difference consists in the formation of a bony bridge in this situation, which gives to the 

 suboccipital foramen a double opening in the hyamas and civets, whereas it is single in 

 the cats." 



In Daphcenus, it is- interesting to observe, the foramina of the atlas are in all respects 

 like those characteristic of the cats and thus depart in a very marked Avay from the 

 arrangement found in the recent Canidce. The transverse processes are broken away, so 

 that their shape is not determinable, but enough remains to show that the atlanteo-diapo- 

 physial notch is not converted into a foramen, thus agreeing with the canines and felines 

 and differing from most of the hyaenas and civets. 



The axis is likewise feline rather than canine in its general character and appear- 

 ance. The centrum is elongate, narrow and depressed, with a thin and inconspicuous 

 hyj)apophysial keel, running along the ventral surface, and has a slightly concave posterior 

 face. The articular facets for the atlas are convex and rise higher upon the sides of the 

 neural canal than in Canis, and on the ventral side they project below the level of the 

 centrum, so that they are separated by a broad notch, which is not present in the modern 

 dogs, and is not w r ell marked in the cats. The odontoid process is a long, slender, bluntly 

 pointed peg, with a heavy, rounded ridge upon its dorsal surface, which is continued 

 back along the floor of the neural canal. The transverse processes are quite long and 

 relatively very stout; they are shorter and heavier than in Canis, and keep more nearly 



