140 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
anus. There is much less chestnut on the legs, and their antero-internal faces are pure yellowish 
white, instead of grizzled gray and black. The tail is very long, measuring 16 inches to end 
of vertebrze, and 19 to end of hairs. The body measures 28 inches to root of tail. 
These differences are, however, not enough to indicate a different species, at least, unless 
supported by additional specimens from this and other localities. The specimen collected by 
Dr. Newberry approaches the present in some particulars. 
The skull of the gray fox (No. 968) exhibits in general the elongated form of the foxes, 
although the muzzle is much shorter and more slender than in those of which the Vulpes fulvus 
is the type. Thus, the distance from the incisors to the anterior portion of the orbit is but 
little more than one-third the total length of the head, instead of being little less than one- 
half. The nasal bones themselves are about one-third the total length of the skull, while in 
the red foxes they are two-fifths. The distance from incisors to point of orbital process of the 
frontal bone is but little more than half the total length of head, instead of being much more. 
The distinctions are, however, perhaps most strikingly seen in the character of the temporal 
crests and the shape of the lower jaw. These crests form a lyre-shaped figure on the top of the 
head, commencing with the occipital crests, which, passing a little forward and inward, come 
in contact with each other about a quarter of an inch anterior to the plane of the occiput, 
separated, and the interspace sometimes filled up, by the interparietal. On touching, these 
crests diverge rapidly in a gentle curve, convex outwards, and attain their greatest separation 
(about an inch) a little beyond the middle of the parietal ; they then approximate again, coming 
closest at the fronto-parietal suture (about 3 of an inch apart;) then again diverge, curving 
slightly outwards to the orbital process of the frontal. The ridge is very distinct on both sides, 
depressed and rounded ; most elevated just behind the orbital process. The space between the 
ridges or crests of opposite sides is smooth and slightly convex ; below the crests, the temple is 
much roughened for the attachment of the muscles. The orbital process is angular; convex 
before, concave behind ; there is a deep longitudinal fossa along its base within, and along the 
temporal crest, which is continued backwards as a shallow gutter to the junction of the two 
crests ; there is also a slight concavity across the posterior portion of the process. 
In the red foxes, on the other hand, the temporal crests of opposite sides are very close 
together, and sometimes form a single median one for some distance after leaving the occiput, 
or are so Closely approximated that there is but little space between them. Nearly or quite in 
contact at the fronto-parietal suture, they rapidly separate and run off along the posterior border 
of the orbital process. This ridge does not project, as in the gray foxes, above the level of the 
skull, nor is the supra-orbital fossa so deep. 
Another striking peculiarity in the skull of the gray, as distinguished from the red foxes, 
is seen in the outline of the suture of the malar bone with the upper maxillary. In the red 
foxes the anterior base of the malar is deeply bifurcated, one branch extending a considerable 
distance downwards, nearly continuous with the lower edge of the bone, and another branch 
passes along nearly horizontally, leaving a deep and almost rectangular notch between the two. 
In the gray foxes, however, although there is a partial bifurcation, the downward branch is 
very short and broad, instead of running to a point. The horizontal branch is little above the 
level of the others, and sometimes the suture passes obliquely across, with scarcely any indication 
of an angle. 
The skull of the gray fox exhibits, in the peculiar character of its temporal ridges and the 
