254 EXPLORATION OP THE CANONS OF THE COLORADO. 
The longer claws are much compressed, moderately curved, acute, falcate, or 
sharp-edged underneath, except at the end, where the sides separate with a 
slight excavation. The back of the hand is moderately pilous, with short, 
soft hairs; the toes being fringed with rather longer and more bristly ones. 
The perfectly smooth and naked palm ends behind in an immense protuber 
ance (as elsewhere in the family), which consists, in effect, of an exterior and 
an interior callosity, united by a slightly-constricted isthmus. This wrist-bulb 
is overhung by a special tuft of short, bristly hairs. The sole is naked like 
the palm, but much narrower and longer (the equality in total length of hand 
and foot being brought about by the length of the fore claws) ; it contracts 
regularly from before behind, ending in a prominent but narrow calcaneum. 
The upper surface of the foot is hairy like the back of the hand. The 3d 
digit is longest ; the 2cl and ^th are subequal to each other, and the tips of 
their claws reach about to the base of the middle claw. The 1st and 5th are 
again about equal to each other, but abruptly much shorter than the others ; 
the tips of their claws hardly or not attaining the base of the 2d and 4th 
digits. The hind claws are of the same character as those of the hand, but 
very much shorter. 
The tail, as in other species of the family, is surrounded at base by a 
conical enlargement a prolongation of the body, haired like the rest of the 
frame, which, in the rutting-season, becomes highly tumid underneath, render 
ing it still more difficult to say where the tail actually begins. Measured from 
its true base, as well as this can be ascertained without dissection (from the 
true base as far as external form is concerned), the tail is more than one-third, 
but decidedly less than one-half, of the length of head and body together 
say about two-fifths. In an average specimen, 7 incjies long, the tail may be 
about 2.75. Measured from where the long hair of the body ceases, or from 
its apparent base, the tail is about one-third of the length of head and body. 
This member is somewhat quadrangular, the flattening being especially notice 
able underneath ; it gradually tapers to an obtuse tip, and is pilous throughout, 
being clothed with short, soft hairs like those covering the hands and feet. 
In the male as well as in the female, the genital aperture is immediately 
in front of the anus. In the rutting-season, the enlargement of the parts is 
chiefly post-anal; there being a great swelling behind the anus, which carries 
the anus away from the apparent base of the tail. The os penis is a slender, 
