336 



NOTES ON THE CANID^E OF THE WHITE RIVER OLIGOCENE. 



hemispheres narrow and short, and the olfactory lobes very large. The partially exposed 

 cast of the cerebral fossa shows that the cerebral convolutions are fewer, simpler and 

 straighter than in any known species of Can is, and are even more primitive than those of 

 Cynodesmus (see Scott, '94, PL I, Fig. 2). The only sulcus visible in the sjjecimen is 

 apjoarently the suprasylvian, which is short and pursues a nearly straight course, but 

 curving downward slightly at both ends. From the external character of the skull it is 

 clear that the hemisjaheres overlap the cerebellum but little. 



Measurements. 



No. 11421. 



Skull, length 



Cranium, length f r. occ. condyles to preorbital border 



Face, length in front of orbits 065 



Zygomatic arch, length 



Palate, length.. 076 



" width at p A 044* 



Mandible, length from chin to masseteric fossa 084 



depth at m T 020 



" "Px 0175 



thickness at m r 010 



No. 11424. 



No. 10538. 



No. 11423. 



No. 11425. 



?0.151 



- 







.108 









?.0o0 



.073 







.080 



.092 







.047* 



.052 











.093 



.096 



.018 





.023 



.025 



.0:5 





.017 



.020 



.00!) 





.010 



.012 



No. 11422. 



?.079 

 .025 

 .019 

 .012 



'Approximate. 



III. The Vertebral Column'. 



The vertebral column is remarkable in many ways. All the regions of the column 

 are well represented by several specimens of J>. vetus and J), hartshornianus, but no com- 

 plete backbone belonging to a single individual has as yet been recovered. 



Cervical Vertebrae. The collection contains only a single imperfect specimen of the 

 atlas and this belongs to D. vetus. Imperfect as it is, this atlas displays some important 

 differences from that of Canis and most of these differences are approximations to the 

 feline and viverrine types of structure. In Daphcenus the atlas is elongate in the 

 antero-posterior direction, the anterior cotyles are small and only moderately concave, 

 and are somewhat more widely separated on the ventral side than in Cards. When 

 viewed from above, the cotyles are seen not to project so far in front of the neural arch 

 as in the cats, but farther than in the dogs. The jiusterior cotyles for the axis are small, 

 nearly plane, and but slightly oblique in position, with reference to the fore-and-aft 

 median line of the vertebra. These cotyles are more distinctly separated from the 

 articular surface for the odontoid process of the axis than in the modern dogs, in which 



