118 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
A comparison of the only two skeletons of prairie wolf before me gives the following results 
as the difference between the prairie wolf of the Platte (No. 1326) and the coyote of El Paso, 
Texas (1001.) The former is a larger and heavier animal, and is marked female, from three to 
. five years. The latter has no indication of age or sex. 
In the Platte skeleton the vertebra are heavier, and their bodies much longer than in the 
other, thirteen dorsal and lumbar vertebre of one corresponding in length to fourteen of the 
other. The long bones, too, of 1326 are much the stoutest and thickest; the humerus and 
femor are of nearly the same length, rather longer in 1326. The fore arm and tibia, however, 
of the Texas specimen are very appreciably longer than in 1326, the tibia of 1001 exceeding 
that of 1326 by nearly half an inch. The heads of these species measure respectively 6.73 and 
6.50 inches. 
It thus appears that the Texan animal is relatively shorter, more delicately built, and with 
longer fore arm and leg. The vertebral formule are as follows: 
LOOM C27 DAS Le GS. 3h Calo texas: 
1326:—C aie Dalss ln TAS. 3c.C20ceP latte: 
The skull of No. .483; from the San Francisco mountains exhibits in a more marked degree 
the difference in breadth referred to above than any other, and it would really seem as if the 
coyotes of the central regions of North America, along the Southern Rocky Mountains, differed 
specifically from those of the Missouri, as indeed ina measure from those of California and 
Eastern Texas. Thus, on comparing the skull of No. 483 with one from the Platte, corres- 
ponding as nearly as possible with it in general characteristics, the least distance between the 
orbits is 1.44 of an inch instead of 1.28, the latter being much the greatest width of any of 
25 Missouri skulls; in these the more usual distance is from one inch to1,5. The distance 
between the points of the orbital process in the skull of 483 is two inches ; fully half an inch 
greater than in most of the Missouri skulls. The skull between the orbits is nearly plane, with 
a slight depression towards the centre. The lower jaw is more undulating in its lower outline, 
and is narrower just back of the molars. 
There are no characteristic differences in the teeth; the third lower premolar lacks a small 
lobe on the middle of the posterior edge seen in the other skull. The upper sectorial is rather 
shorter and wider anteriorly. These differences, however, may be readily noticed in skulls 
from the same locality. 
Upon the whole, I find, then, that specimens from the vicinity of the Rocky Mountains differ 
very appreciably in the skull and skeleton from those of the Upper Missouri; the one having 
a broader and flatter forehead, more slender bones and longer fore arm and tibia, the other 
having a greater depression in the middle of the interorbital space, less width between orbits 
and orbital processes, and larger sectorial tooth. Whether external differences exist can only 
be determined by more specimens. A specimen from Eagle Pass, Texas, has shorter ears and 
brighter colored legs than any other; its skull is intermediate in width and flatness of inter- 
orbital region between the Rocky Mountain and Missouri specimens. The Canis frustror of Dr. 
Woodhouse is a very young animal, two specimens of which differ very appreciably from each 
other. Specimens from any given locality differ in amount of black on the body, size of the 
tail, general color, softness of fur, width of skull, and of interorbital space. 
If a name be appropriate for any specimens as distinct from QC. latrans, it is most applicable 
to the El Paso, Coppermines and San Francisco mountain ones. The name of C. ochropus will 
not answer, as they differ from California coast specimens as much as from those of the Missouri. 
