126 SCIURUS. 
Measurements. Total length, 460; tail vertebre, 230; hind foot, 
55. Skull: basal length, 45; palatal length, 23; interorbital width, 
16.2; zygomatic width, 19; length of upper molar series, 9.5. 
a.—baliolus (Sciurus), Nelson, Proc. Biol. Soc. Wash., xIv, 1901, 
tae 
SWARTHY SQUIRREL. 
Type locality. Apazote, State of Campeche, Mexico. 
Geogr. Distr. Southern part of State of Campeche, and eastern 
part of State of Tabasco, Mexico. 
Genl. Char. Similar to S. yucatanensis, but darker. 
Color. Above blackish gray suffused with buff; beneath iron 
gray; legs and hands grizzled with buff or gray; feet black; tail black, 
washed with gray. 
Measurements. Total length, 464; tail vertebrz, 238; hind foot, 
59- 
89. thomasi (Sciurus), Nelson, Proc. Wash. Acad. Scien., 1, 1899, 
pe 7a: 
boothie (nec Gray), Allen, Mon. N. Am. Rodent., 1877, pp. 741- 
7460. (Part. Costa Rica.) 
hypopyrrhus Alston, Proc. Zodl. Soc., 1878, pp. 662-664. (Part. 
Costa Rica specimens. ) 
THOMAS’ SQUIRREL. 
Type locality. Talamanca, Costa Rica. 
Geogr. Distr. ‘‘Humid tropical forests of eastern Costa Rica.”’ 
Genl. Char. Hair on back coarse, stiff, glossy; tail long, narrow. 
Color. Crown and upper parts of body, sides of neck, outer side 
of arms and Iegs, and base of tail black, the yellowish under color 
appearing; chin and sides of head grayish brown; under parts ferru- 
gineous, irregularly varied with white; tail above black, washed with 
white, beneath grizzled black and yellowish brown, bordered with 
black and edged with white; feet black or grizzled ferrugineous; ears 
blackish, with basal ferrugineous patch, and black tufts. 
Measurements. Average total length, 517.5; tail, 246.5; hind foot, 
62.2. Skull: basal length, 50; palatal length, 26.2; interorbital width, 
22; zygomatic width, 35.5; length of upper molar series, 11.5. 
90. adolphei (Macroxus), Less., Nouv. Tabl. Régn. Anim. Mamm., 
LOAQi). Fa, 
bootue Allen, Mon. N. Am. Rodent., 1877, p. 741. (Part. 
Nicaragua.) 
hypopyrrhus Alston, Biol. Centr. Amer. Mamm., I, 1880, p. 128. 
(Bart) 
