36 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
heavier, wider, especially across forward part of zygoma incisor teeth orange 
(yellow in O. costaricensis). 
Color. — Upper parts bright yellowish red brown, darkest along middle of 
back, and becoming strong orange rufous on rump and sides, sides of head and 
at base of whiskers ; top of nose and head duller and more mixed with dark 
brown-tipped hairs; chin and under side of neck whitish, rest of under parts 
ochraceous buff, not sharply contrasted with color of sides ; feet and hands yel- 
lowish white; ears dark brown outside, inside with hairs— rather sparse — 
colored like the back; tail dusky above, grayish below. Young examples 
differ little from the adults, except in being rather duller in color throughout. 
Measurements — 
No. Sex. Total length. Tail vert. Hind foot. Ear. 
10,304 & old ad* 235 130 24 13-ae 
10,306 Q old ad. 220 130 24 13 
10,303 & ad. 215 120 25 13 
10,298 type @ old ad. 210 120 25 14 
10,302 & ad. 208 LLG) 24 13 
10,297 & ad. 206 120 24 13 
10,295 & ad. 205 120 24 13 
10,300 & yg. ad. 200 118 24 13 
10,310 & yg. ad. 190 115 24 12 
10,305 & yg. ad. 190 110 25 12 
10,309 d yg. 170 98 22 12 
Skull. — Type, old ad. @, basal length, 20.2; occipito- 
nasal length, 24.4; zygomatic width, 12.6; mastoid width, 
11; interorbital width, 3.4; length of nasals, 9; upper 
molar series, 2.8 ; length of single half of mandible, 12.4. 
Remarks. — O. vegetus may prove to be only a northern 
subspecies of O. dryas humilior Thomas of Colombia, Bo- 
gota region to Santa Marta region. Though closely allied, 
the Chiriqui form has a shorter tail, is rather redder above, 
and slightly paler below, and its skull is decidedly heavier 
throughout. 
On the Volcan de Chiriqui the two species of pigmy 
Oryzomys occur together. In the Santa Marta Moun- 
tains, where two species, O. dryas humilior and O. navus, 
also occur, the former was found from 8,000 to 9,000 feet 
Fie. 15. Oryzomys only, and the latter from 3,000 to 8,000, their ranges just 
vegetus. Type. overlapping. 
x 1 
