SCIURUS, l 
Fia, 20. SCIURUS (HH ESPEROSCIURUS) GRISEU 
No, 660% Mield Columbian Mus, Coll Nat, size 
Geogr, Distr, Oregon and northern California, into Lower Califor 
nia, Mexico 
Genl, Char. Size large; tail vertebra as long as body and head; 
upper premolars and molars, five; skull slender, elongate 
Color Above and outside of arms and legs grizzled bluish gray 
and black; under parts pure white; tult at base of ear chestnut 
tail above mixed gray, white, and black, with a white border, beneath 
grizzled grayish white, with sometimes an ill-defined border and white 
edge; hands grayish white to grizzled gray; feet gray to blackish gray 
Measurements, Total length, 565; tail vertebra, 257; hind foot, 
77, Car, 30% Skull: average of five; basal length, 56.3; palatal 
length, 32.1; int@rorbital width, 20.8; zygomatic width, 38.7; length 
of upper molar series, 11 " 
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