1891.] ‘ Zoology. 159 
back of the nose, passes between the darker shade of the crown and a 
superorbital white area, terminating at the ear. 
The upper border of the white of under parts is defined by a line 
drawn from the nostrils, passing over the eyes and through centers of 
ear openings, across shoulders and along sides of body to the groins. 
The white area also includes the inner surfaces of legs and dorsal sur- 
faces of hind feet, which latter are slightly washed with rufous, Hairs 
of under parts entirely white, but so thin in the specimen before me 
that the color of the skin shows through, giving a plumbeous cast to 
most of this surface. 
Outer surface of fore limb, from elbow to bases of toes, white, more 
or less washed with rufous. Outer surfaces of hind legs concolor with 
dorsum. 
First third of upper surface of tail the same as back; thence the 
center is fawn color, bordered bya black zone that, in turn, is bordered 
by a wĦitish rufous. On its under surface the black line is. scarcely 
` perceptible, the whole of this surface being pale rufous. 
Ears, in dried skin, a mere rim, 
Lower surfaces of pes densely haired ; of manus, 
Claws medium sized, black, with white R Upe; s oE Homb. as well de- 
veloped as in S. mextcanus. 
Mystacial hairs mostly black ; a few white ones interspersed. 
Measurements of dried skin, in millimeters: Total length, 220; 
head and body, 155; tail vertebra, 65; hairs beyond vertebre, 20; 
hind foot, 33; fore foot, 21; longest mystacial hairs, 32. 
Measurements of skull: Length from point of nasals to upper edge 
of foramen mgnum, 38; greatest width at auditory bullæ, 18; least 
interorbital width, 9 ; length of molar series, 8.5 ; transverse diameter 
of first premolar, 1.25 ; the same of second, 2; of first molar, 2.5. 
The zygomz and hinder edge of palate are broken, so as to allow of 
no measurements being taken from them. 
The only noticeable differences between this skull and that of .S. 
cryptospilotus (vide North American Fauna, No. 3, Pl. 1x., Figs. 1, 
2, and 3) is that in this the hamular processes of the pterygoids abut 
against the auditory bullæ posterior to the suture of the basisphenoidum 
with the basioccipitale, instead of in front of it, as in cryptospilotus ; 
and in that the transverse diameter of the first premolar is fully equal 
to its longitudinal diameter. 
_ _ Type: No. 517 8ad., Museum of the Comision Geografica-Explora- 
dora de México. Taken by Zenon Cordova, at Hermosillo, Sonora, 
November, 188 87. 
Am. Nat.—February.—5. 
