254 ZYGODONTOMYS. SIGMODONTOMYS. 
SUERRE RicE Rat. 
Type locality. Suerre, Costa Rica. 
Geogr. Distr. Costa Rica, Central America. 
Genl. Char. Size medium; tail half the length of head and body; 
ears small. Skull has the superciliary bead very broad; anterior 
palatal foramina not reaching anterior base of the first molar. 
Color. Above mixed blackish brown and yellowish rufous; 
brighter on the sides; under parts yellowish brown tinged with gray; 
tail uniform black; hands and feet blackish brown; ears black. 
Measurements. Total length, 187; tail, 90; hind foot, 25; ear, 
from notch, 10.5. Skull: total length, 28; basal length, 23.5; zygo- 
matic breadth, 15; palatal length, 5.3; width of braincase, 12; length 
of nasals, 9.5; length of upper tooth row, 5.3. (ex Type.) 
247. seorsus (Zygodontomys), Bangs, Am. Nat., xxXv, 1901, p. 642. 
IsoLaTED Rice Rar. 
Type locality. San Miguel Island, Bay of Panama. 
Genl. Char. Similar to Z. brevicauda from Trinidad, but larger; 
tail scales coarse; skull larger, characters more pronounced. 
Color. ‘‘Upper parts russet brown, shaded with dull ferru- 
gineous, the latter more intense on the rump; whole dorsal region 
thickly set with brownish black-tipped hairs; sides paler, more yel- 
lowish; under parts dull buffy gray, strongly shaded with dull ferru- 
gineous on anal region; line of demarcation between colors of upper 
and under parts indistinct; upper surface of hands and feet yellowish 
brown; soles naked; ears sparsely haired, dusky; tail very sparsely 
haired, coarsely scaly, indistinctly bicolor, blackish, rather paler 
towards base below.”’ 
Measurements. Total length, 280-320; tail vertebra, 110-140; 
hind foot, 30-34; ear from notch, 15-18. Skull: basal length; 32.8; 
occipito-nasal length, 35.2; zygomatic width, 18.4; mastoid width, 
12.8; length of nasals, 15; width of nasals, 4.4; interorbital constric- 
tion, 5.4; width across zygomatic plates, 11.2; length of incisive 
foramina, 7.4; width of incisive foramina, 3.2; length of palate, to 
palatal notch, 16; to end of pterygoid, 22; upper tooth row, 5.2; length 
of single half mandible, 21; lower tooth row, 5.2.’’ (Bangs, l. c.) 
51. Sigmodontomys. 
Sigmodontomys Allen, Bull. Am. Mus. Nat. Hist., 1897, p. 38, pl. 
1, figs. 8-14. Type Stgmodontomys aljart Allen. 
Nasals narrowing posteriorly, pointed; anterior palatine foramina 
broad, not reaching front molars; palate reaching beyond posterior 
line of molars; palatal fossa broad, pterygoids parallel; base of 
