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PSEUDOSTOMA UMBRINUS.-Rich. 
Leadbeater’s Sand Rat. 
G-. Super urnbrinus, subter griseus, gula pedibusque albidis, cauda grisea 
vestita longitudine capitis. 
CHARACTERS. 
Umber brown on the dorsal aspect, grey below, with white feet and throat, 
and a grey hairy tail as long as the head. 
SYNONYMES. 
Geomys Umbrinus. — Rich, Fauna Boreali Americana, p. 202. 
Dr. Le Conte, Proc. Acad. Nat. Sci., Pliila., 1852, p. 162. 
DESCRIPTION. 
Head large, nose wide and obtuse, and with the exception of the nos- 
trils, covered with fur similar in colour and quality to that on the crown 
of the head. The nostrils are small round openings, half a line apart, 
with a furrowed septum, and having their superior margins naked and 
\aulted ; a narrow, hairy, upper lip, not exceeding a line in width, sepa- 
rates the nostrils from the upper incisors. The whiskers are white, and 
are shorter than the head. The incisors are much exserted, and are with- 
out grooves on their anterior surfaces, which are slightly convex, and of 
a deep yellow colour. The lips unite behind the upper incisors, so as to 
form a naked furrow leading towards the mouth, which is rendered more 
complete by the stiffness of the hairs on each side of it. The cheek 
pouches are of a soiled buff colour, and are clothed throughout their exte- 
rior surface with very short, soft, whitish hairs, which do not lie so close 
as entirely to conceal the skin. The middle of the pouch is opposite to 
the ear, and its anterior margin extends forwards to between the eye and 
the angle of the mouth ; its tip is rounded. 
The body, in shape, resembles that of a mole. It is covered with a 
smooth coat of fur, of the length and quality of that of a meadow mouse ; 
but possessing more nearly the lustre and appearance of the fur of a musk 
t 
