MAMMALS CANIDAE VULPES VELOX. 135 



There are some points of resemblance between this fox and the Vulpes lagopus in size, shape 

 of skull and tail. The difference of color between the grizzled yellowish gray of the one, and 

 the pure white or sooty gray of the other, will always distinguish them. Canis griseus of Chile 

 is of about the same size, but has a more wolf-like tail. The skull is very different, the animal 

 belonging to the subgenus Lycalopex, (now Pseudolopex,} of Burmeister. 



The relationship of this species to the Canis corsac is very close, as, without specimens of the 

 latter, I am unable to find in descriptions any trenchant distinctive features. 



Summer specimens of this fox, received since the preceding description was prepared, differ 

 very materially from the winter dress. The size is considerably smaller ; the fur much shorter 

 on all parts of the body; the tail is full, cylindrical, constricted at the base, and obtusely pointed 

 at the tip. The feet are quite thinly haired. There are small naked pads under all the toes, 

 and a V-shaped one under the palm. There is no entirely naked ball under the metatarsus, 

 the one sometimes found there being overgrown with short hairs. 



There is decidedly more of a reddish tint in these specimens, replacing the yellowish of the 

 other, including the basal of the back and sides. The under surface of the tail is cinnamon- 

 colored, darkest towards the extremity. The tip of the tail is decidedly and conspicuously 

 black, without any white hairs. The size of the two specimens is about the same, 1827 rather 

 larger, fuller, and more cinnamon in tint. 



The skull of the little prairie fox exhibits a very close resemblance to that of the red fox 

 although much smaller. The upper outline is almost precisely the same, perhaps more convex 

 about the meatus. The temporal crests in seven skulls before me do not approach each so much 

 as in the red fox, the shape (lyre-form) and distance of the ridges more like what is seen in the 

 gray fox, although otherwise this is a very different animal. The post-orbital processes of the 

 frontal bone are rather short, and are more obtuse than in the red fox. The temporal fossae 

 are considerably larger in proportion, and the distance between the zygomata wider. The sides 

 of the skull at the temples are considerably more convex. The forehead is rather flatter. The 

 orbital process is further back. The lower jaw is very similar in shape to that of the red fox, 

 although its lower outline is more curved. 



The dentition is almost exactly that of the red fox, the differences being with difficulty 

 expressible by description. There is but a single trihedral tubercle on the posterior lower 

 molar. The lower canines are shorter, broader at base, more curved, and the angle nearer 

 the middle of the exposed portion than in the red fox, in which the bend is nearer the base. 



The skull of this species is considerably smaller than that of the Arctic fox, Vulpes lagopus, 

 the muzzle is much slenderer and the outline of the sides more concave. The anterior half of 

 the zygoma is broader than the posterior, instead of narrower, as in the Arctic fox. The upper 

 branch of the anterior root of the zygomatic arch is much more horizontal. The muczle, also, 

 is not so high, and the free edge of the intermaxillary is more oblique. 



I am inclined to think that at no age are the temporal crests of Vulpes velox ever united into 

 one beyond the termination of the interparietal bone. In a specimen having every appearance 

 of extreme age, these ridges are half an inch apart at the coronal suture. 



The resemblance of the skull of Vulpes velox to that of Canis corsac, as figured by Blainville, 

 is exceedingly close. The size is precisely the same, and all the details appear almost identical. 

 The only appreciable difference is that in C. corsac, the inferior or posterior fork of the anterior 

 root of the zygomatic arch does not project forward at all, the outline of contact with the 

 maxillary being an obtuse angle, instead of a narrow loop bent round with the branches beyond 



