Besides this disparity of dentition in the red and gray foxes, the general form of the cranium, and its particular detailed characters, as a less elevated occipital, and temporal crest, more profoundly sinuous junction of the malar with the maxillary bone, the absence of elevated lines bounding the space between the insertions of the lateral muscles, passing in a slightly reclivate direction between the orbital processes, and the anterior tip of the occipital crest, and in particular the want of an angular process of the lower jaw beneath the spinous process in the cranium of the red fox, are sufficiently obvious characters to indicate even by this portion of the osseous structure alone, its specific distinctness from the gray fox. In these differences the osteology of the burrowing fox equally participates, and although besides these characters in common with the red fox, we may observe a correspondence in many other respects, yet there are also many distinctions which the cranium of this small species will present, when more critically compared with that well known animal, which unequivocally forbid us from admitting their identity. The common elevated space on the parietal bones between the insertions of the lateral muscles is one-fourth wider, and extends further backward, so as to embrace a notable portion of the anterior angle of the sagitto-occipital crest; the recipient cavity in the inferior jaw for the attachment of the masseter muscle is more profound, and the coronoid process, less elevated than the top of the zygomatic arch, is more obtusely rounded at tip than that of the red fox. The dimensions of the cranium, as taken by the calipers: The entire length from the insertion of the superior incisores to the tip of the occipital crest, is rather more than four inches and three-tenths. The least distance between the orbital cavities, nine-tenths. Between the tips of the orbital processes less than one inch and one-tenth. Between the insertions of the lateral muscles, at the junction of the frontal and parietal bones, half an inch. Greatest breadth of this space on the parietal bones thirteen-twentieths of an inch. The hair is fine, dense, and soft. The head above is fulvous, drawing on ferruginous, intermixed with gray, the fur being of the first-mentioned colour, and the hair whitish at base; then black; then gray; then brown. The ridge of the nose is somewhat paler, and a more brownish dilated line passes from the eye to near the nostrils, (as in the C. corsac). The margin of the upper lip is white; the orbits are gray; the ears behind are paler than the top of the head, intermixed with black hairs and the margin, excepting at tip, white; the inner side is broadly margined with white hairs; the space behind the ear is destitute of the intermixture of hairs; the neck above has longer hairs, of which the black and gray portions are more conspicuous; beneath the head pure white.