SCIURUS. 107 
PAGE 
c.’’ Above gray; tail beneath cinnamon. .S. nayaritensis 108 
d.’’ Above mixed gray, black, white, and 
tawny; tail beneath tawny .......... S. arizonensis 109 
e.’’ Above grizzled gray; tail beneath pale 
ENCSS Gin DERE eet die ea S.a.huachuca 109 
b.’ Under parts buffy yellow to orange yellow....S. apache 110 
74. oculatus (Sciurus), Peters, Monatsb. K. Preuss. Akad. Wiss. Berl., 
1P303,,/p. 653. 
captstratus Licht., Abh. K. Akad. Wiss., 1827, p. 116. (nec Bosc.) 
carolinensis Sauss., Rev. Mag. Zool., 2me Sér., x1, 1861, p. 4. 
(nec Gmel.) 
hypopyrrhus Allen, Bull. U. S. Geol. Surv. Terr., tv, 1878, p. 881. 
(Part.) 
niger melanonotus Thomas, Proc. Zodl. Soc., 1870, p. 73, pl. vi. 
BLACK-BACKED SQUIRREL. 
Type locahty. Las Vigas? State of Vera Cruz, Mexico. 
Geogr. Distr. Northwestward through States of Vera Cruz, 
Hidalgo, Queretaro to southeastern San Luis Potosi, Mexico. Allti- 
tude, 6,000-12,000 feet. 
Genl. Char. Size large; skull broad and heavy. 
Color. Upper parts dark gray, with a black band from middle of 
crown to base of tail; orbital ring whitish; cheeks and sides of neck 
grizzled gray with a buff tinge, not always, however, present; ears 
dull gray with white or buff basal patches; hands and feet grizzled 
gray or buffy; outside of arms and thighs gray, sometimes rusty 
brownish on the thighs; under parts white with buffy tinge to ochra- 
ceous buff; tail above black washed with white, beneath grizzled 
gray, tinged with yellowish, bordered with black and edged with 
white. 
Measurements. Total length, 544; tail vertebre, 254; hind foot, 
69. Skull: average of three; basilar length, 54.6; palatal length, 
28.5; interorbital width, 20.3; zygomatic width, 36.3; length of upper 
molar series, I1. 
a.—toluce (Sciurus), Nelson, Proc. Biol. Soc. Wash., x11, 1898, 
py 148. 
ToLuca SQUIRREL. 
Type locality. North slope of the Volcano of Toluca, State of 
Mexico, Mexico. 
Geogr. Distr. Sierra Madre from Toluca Volcano, State of 
Mexico, to border of State of Michoacan; southern and western 
parts of State of Queretaro; central and eastern parts of State of 
Guanajuato, and southern part of State of San Luis Potosi, Mexico. 
