330 KOTES OS THE CAXID^ OF THE WHITE KIVER OLIGOCESTE. 



II. The Skull (PI. XIX, Figs. 1-7). 



The skull of Daphcemis is exceedingly primitive in character and plainly shows 

 many traces of the creodont ancestry of the genus. Unfortunately, well-preserved skulls 

 are exceedingly rare and none of the species is represented by an altogether complete 

 specimen. However, several more or less imperfect sjjecimens have been recovered, 

 which together give us information concerning nearly all parts of the skull. 



As in the creodonts generally, the cranial region, reckoning from the anterior edge 

 of the orbits backward, is exceedingly elongate, while the face in front of the orbits is 

 very short, slender and tapering. The elongation of the cranium is not due to an enlarge- 

 ment of the cerebral fossa, which on the contrary is short, narrow and of relatively small 

 capacity. The postorbital constriction, which marks the anterior boundary of the cerebral 

 fossa, is notably deep and is removed much farther behind the orbits than in Can is. On 

 the other hand, the cerebellar fossa is long, and the postglenoid processes occupy a more 

 anterior position than in the existing species. In consequence of the elongate cranial 

 region, the zygomatic arches are very long, as in the more primitive types of creodonts. 

 The upper contour of the skull is nearly straight, the descent at the forehead being very 

 slight and gradual, which gives to the skull an alopeeoid rather than a thooid aspect. 

 This resemblance is, however, entirely superficial, for the frontal sinuses are large and 

 well developed, as in the thooid series of the modern Canidce. The sagittal crest is low, 

 but varies in the different species, being decidedly thicker and more prominent in the 

 larger and heavier I), vetus than in the smaller and lighter I), hartshorn ianus. 



Turning now to the more detailed study of the elements which make up the skull, 

 we shall find a number of striking and significant differences from the existing repre- 

 sentatives of the family, though the general aspect of the whole is distinctively canine. 



The basioccipital is broad and quite elongate and has a much more decided median 

 keel than Ganis. All the occipital bones are firmly ankylosed in the specimens at my 

 disposal : hence, in the absence of sutures, it will be necessary to describe the compound 

 bone as a whole, without much reference to the elements of which it is made up. The 

 occiput is of quite a different shape from that found in the existing members of the 

 family, being broader, lower, and with a wide, gently arched dorsal border or crest (see 

 PI. XIX, Fig. 3); in Canis this crest is pointed and somewhat like a Gothic arch in 

 shape. The occipital crest is thin, but much more prominent than in Ganis, which is 

 due to the larger and deeper depressions of the cranial walls behind the occipital lobes 

 of the cerebral hemispheres, the shape of which is plainly visible externally. The 

 foramen magnum has much the same low and broad outline as in Canis. The 

 condyles are low. but well extended transversely, and on the ventral side they are sepa- 



