THOMOMYS. 339 
Genl. Char. Small, similar to T. toltecus, but grayer and smaller. 
Nasals notched behind and terminating on plane of premaxille; 
interparietal subquadrate; braincase swollen. 
Color. Above mixed drab gray and black; sides buffy; rump 
and sides of shoulders buffy fulvous; under parts, fore legs, and 
feet buffy salmon; hind feet whitish; space around mouth dusky. 
Measurements. Total length, 195; tail vertebre, 59; hind foot, 
26.5; 
343. sinaloz (Thomomys), Merr., Proc. Biol. Soc. Wash., xiv, 1901, 
p. 108. 
SINALOA PocKET GOPHER. 
Type locality. Altata, State of Sinaloa, Mexico. 
Geogr. Distr. Known only from the type locality. 
Genl. Char. Similar to T. cervinus, but darker. Skull has 
“strongly spreading, depressed, and sharply angular zygomata.”’ 
Color. Above pale chestnut brown; under parts pale chestnut 
fulvous; space around mouth pale dusky. 
Measurements. Total length, 233; tail vertebrae, 73; hind foot, 31. 
344. goldmani (Thomomys), Merr., Proc. Biol. Soc. Wash., xrv, 
IgOl, p. 108. 
GOLDMAN’s Pocket GOPHER. 
Type locality. Mapimi, State of Durango, Mexico. 
Geogr. Distr. Range unknown. 
Genl. Char. Very small, allied to T. perditus. Nasals shorter than 
premaxille. 
Color. Above ‘bright rusty fulvous, mixed with dark-tipped 
hairs; under parts white; nose and region around mouth dusky.”’ 
Measurements. Total length, 208; tail vertebra, 68; hind foot, 30. 
345. nelsoni (Thomomys), Merr., Proc. Biol. Soc. Wash., xiv, 1901, 
py.209- 
NELSON’s PocKEeT GOPHER. 
Type locality. Parral, State of Chihuahua, Mexico. 
Genl. Char. Size medium. Skull: ‘“‘Zygomata strongly spread- 
ing, broader behind than in front, with well developed anterior angle; 
temporal impressions marked; interparietal subquadrate, becoming 
subtriangular in old age; nasals narrowly cuneate, notched behind, 
and falling well short of premaxille; bullae medium; under jaw 
very long, the postcoronoid notch narrow and completely covered 
by coronoid process.” 
Color. Above “dull chestnut brown, mixed with black-tipped 
hairs on middle of back; under parts same color, but paler; nose 
