360 ' PEROGNATHUS. 
Geogr. Distr. Southern part State of Sonora and northern por- 
tion State of Sinaloa, plains of the coast, Mexico. 
Genl. Char. Similar to P. pernix, but skull shorter and wider. 
Color. Above broccoli brown; lateral line pinkish buff; under 
parts whitish; generally paler than P. pernix. 
Measurements. Total length, 162; tail vertebre, 94; hind foot, 
23.5. Skull: occipito-nasal length, 22.7; Hensel, 16.5; greatest mas- 
toid width, 11.7; length of interparietal, 3.4; greatest width of inter- 
parietal, 7; interorbital constriction, 5.5; length of nasals, 8.6. 
363. helleri (Perognathus), Elliot, Pub. Field Columb. Mus., 111, 
1903, p. 166. Zodlogy. 
HELLER’S Pocket Mouse. 
Type locality. San Quentin, Lower California, Mexico. 
Genl. Char. Size similar to P. p. arenarius, color very different, 
conspicuous lateral line. Skull with shorter nasals, broader ros- 
trum, wider interorbital space, braincase broader, mastoids less 
prominent, bulle smaller and more pointed anteriorly. 
Color. Above mixed black and dark buff, giving a dark yellowish 
brown appearance to the upper parts; distinct bright buff lateral 
line from nose to rump; under parts pure white; tail above dark 
brown, almost dusky, beneath pure white, pencil-like upper part 
dusky; hands and feet gray; ears dark brown. 
Measurements. Total length, 159; tail vertebra, 83; hind foot, 
20.5; ear, 8. Skull: occipito-nasal length, 23; Hensel, 14; zygo- 
matic breadth, 11.5; interorbital constriction, 6; mastoid breadth, 
11.5; greatest width of braincase, 10.5; palatal length, 8.5; length 
of nasals, 7.5; width of rostrum, 4; length of upper tooth row, al- 
veolar border, 3. 
364. hispidus (Perognathus), Baird, N. Am. Mamm., 1857, p. 421. 
Elliot, Syn. N. Am. Mamm., 1gor, p. 251. 
Hispip Pocket Mouse. 
Type locality. Charco Escondido, State of Tamaulipas, Mexico. 
Geogr. Distr. States of Nuevo Leon and Tamaulipas, Mexico, 
north into Texas and Oklahoma. 
Genl. Char. Size large; tail about equal to head and body; no 
spines; antitragus lobed; hind foot broad, short. 
Color. Above brownish black and cinnamon; lateral stripe 
bright fulvous; under parts, fore legs, and feet white; tail black 
above, white below; no tuft. 
Measurements. Total length, 208; tail vertebre, 102; hind foot, 
24. Skull: length of Hensel, 20.2; occipto-nasal length, 28; greatest 
mastoid breadth, 13.8; length of interparietal, 4.1; greatest width 
