224 EXPLORATION OF THE CANONS OF THE COLOEADO. 
jaw, about half-way from nose to eye, just underneath the whisker-patch, and 
curves loosely around the side of the head to the angle of the jaw. The 
general outline of the orifice is semicircular (or rather semipyriform, since the 
broadest part sags down a little) ; the inner border being the proper integu 
ment of the side of the head. The lining of the sac is ordinary integument, 
of rather more delicate texture ; it is clothed with fine fur. On the side next 
the head, the ordinary fur of the parts makes directly into the pouch ; on the 
outside, the fine fur continues to the brim, where it is met by the ordinary 
external pelage. Between the two layers of skin rests a thin bed of muscu 
lar fibers (perhaps a modified platysma myoides), serving for such contractile 
movements as the receptacle may be susceptible of. But the connection 
between the folds of skin is so slight and loose that the pouch may, with little 
force, be turned completely inside out, though it does not appear that this 
ever occurs in life. A full-sized pouch will admit three fingers as far as the 
first joint. 
The small eyes are situated midway between the nose and ears, below the 
line between these two ; and, if anything, they are rather nearer the latter than 
the former. The ears have been described in varying terms, leaving a doubt 
whether there was an auricle or not ; but it is proper to say that the auricle 
is obsolete. The large circular orifice of the meatus externus is surrounded 
by a raised brim, rather thicker, if not higher, behind than before, and, as 
such, constituting a rudimentary pinna; but there is nothing to be called a 
flap (which is something that may be turned over). 
The large, strong, and eminently fossorial fore feet recall those of the 
mole in some respects, though they occupy the usual position with reference 
to the axis of the limb sole downward instead of tilted over. The hand 
itself is shorter than the hind foot ; but the immense claws reverse the pro 
portion of the two as a whole. The palm is broader than the sole, and 
perfectly naked. At the juncture with the wrist, it presents two great movable 
callous tubercles, which probably have a bearing upon the great force of flex 
ion of the member ; otherwise the palm is flat, devoid of special pads or cal 
losities, and may be thrown into indeterminate rugse or sulci, according to the 
movements of the parts. There are five digits, whose relative lengths are 
nearly the same as those of the claws they respectively bear. All the claws, 
