558 MONOGRAPHS OF NORTH AMERICAN RODENTIA. i 
without appreciable constriction of the neck, upon which the shoulders seem 
to encroach ; the head is especially broad, the width across the occiput being, 
if anything, greater than the breadth across the shoulders; the limbs are 
short, of approximately equal lengths, massive above the wrist and ankle ; 
the tail is very short; the muzzle is thick and blunt ; the whiskers are long 
and stiff; the ears are of moderate size; the pelage is soft. The whole organ- 
ization, viewed externally, indicates terrestrial and highly fossorial habits. In 
moving, the animal carries the body low, almost sweeping the ground ; at rest, 
the back is arched. 
The head is broad and massive, much compressed in the horizontal 
plane (being wider than deep), and especially noticeable for the flat expanse 
of its upper surface, which is continuous with that of the shoulders without 
depression of the nape, and with scarcely any constriction of the sides of the 
neck behind the ears. Viewed from aboye, the sides of the head taper 
gradually, in nearly straight lines, from the broadest point (at the ears) to the 
snout, which is extremely obtuse. The profile of the forehead is likewise 
nearly straight. The chin is retreating; its under surface is nearly flat; 
the end is broadly convex, like the rest of the obtuse muzzle. The opening 
of the mouth appears contracted from the thickness of the swollen fleshy 
lips. The upper ineisors are probably always exposed. The peculiar shape 
of the head as a whole is correlated with the remarkable preponderance of 
planes and right lines which the skull shows. 
The thick lips are entirely hairy, the upper lip especially being clothed 
with short, stiffsh, antrorse, adpressed hairs for some distance within the 
apparent buccal orifice, and there being a special brush of similar hairs 
directed inward, near the commissure of the lips. Theré is a narrow naked 
muffle, cleft with a well-marked vertical line of impression; a naked pad 
projects from this to the interspace between the upper incisors; a narrow 
margin around each nostril is also naked; otherwise the snout is entirely 
hairy. The whiskers are numerous, very long, and extremely stiff—more 
like hog’s bristles than the whiskers of most Rodents. The longest ones, 
when laid backward, reach entirely beyond the shoulders. These bristles 
are mostly colorless; some of the shorter upper ones, however, are brownish. 
Besides the labial set proper, there are other long bristles, also mostly color- 
less, in tufts over the eyes, and scattered about the ears; both lips are thickly 
fringed with similarly colorless, short, but. still stiff, bristly hairs, in addition 
