620 MONOGRAPHS OF NORTH AM! KHAN RODENTIA. 



are scattered over the tail, and more evidenl ones clothe the instep; bul the 

 parts always present a peculiar skinny appearance. Tail less than one-fourth 

 as lone as the head and body; hands not as long as the feet : smaller and weaker 

 than in the bursarius group; cheek-pouches are not so highly developed. As 



well as can be judged from prepared skins, the sacs do not reach to the 

 shoulder; their capacity, in an individual marh a loot long, seems no greater 

 than that of specimens of G. bursarius not more than half as bulky. Tin; 

 external meatus of the ear has a small flap. The hispid pelage is a remark- 

 able feature, being coarse and harsh, almost entirely lustreless, longer than 

 usual, and interspersed with still longer and almost bristly hairs; and the color 

 is uniform to the roots of the hairs. It is characteristic of all the soft-haired 

 species of Geomijs to have plumbeous-colored fur at base, pointed with the 

 particular brown, fulvous, or other shade which determines the appearance to 

 the eye. In G. hispidus, the hairs are unicolor from base to tip ; dark mahog- 

 any-brown, or rather chocolate, a little lighter or darker according to age or 

 season, or fortuitously, but uniform over all the upper parts and sides. Under- 

 neath, the color is paler, like cafe uu hit; sometimes quite smoky-gray or 

 muddy-brown. The under parts frequently show indeterminate patches of 

 white. It is probable that plumbago-colored individuals occur, but I have 



see me such. The naked parts appear to have been reddish or flesh-colored ; 



claws horn-color; incisors faced with red. 



Note, on a skull. 



In preparing the original memoir, I regretted that I had no skull of 

 either of the Mexican species to describe. Since then I have found a detective 

 specimen in the collection of the National Museum, marked "hispidus — Mex." 

 It is much larger than any United States specimen I have seen, measuring in 

 total length (from occipital crest to incisive alveoli) 2.70 inches, with a width of 

 1.85 across the widest part of the zygomatic arches. (A good-sized speci- 

 men ol G. bursarius measures in the same dimensions 2.25X1-50.) Greatest 

 depth of skull, without jaw, 1.18 (opposite premolars; the corresponding dimen- 

 sion of G. bursarius is only 0.70). Width across occiput, 1.65. Length of 

 lower jaw (condyle to incisive alveolus), 1.80 (in G. bursarius, 1.45); great- 

 est divergence of rami of the jaw (at the exflected angles), 1.80. The enor- 

 mous under incisors protrude more than an inch — 1.25; the upper incisors 

 are exserted for 0.G5. The zygomatic width is increased by a well-marked 



