Oct., 1916. Mammats, Cottins-Day Expepition— Oscoop. 205 
“cheeks, chin, and throat white.” It is difficult, also, to appreciate 
“back of the ears bright red bay”’; and since both of these features are 
found in another specimen obviously belonging to a different species, 
it seems necessary to recognize both ochrescens and ignitus. 
Sciurus langsdorffi Brandt. LANGspoRFF’s SQUIRREL. 
Two specimens, Porto Velho, Madeira River, Brazil. 
Oryzomys sp. 
One specimen (skull only), Parotani. 
Beyond the determination of this skull as a representative of the 
longicaudatus-stolemanni series, no further identification is possible 
with the material at hand. Doubtless it is not the same as the species 
recorded by Thomas* from Charuplaya in eastern Bolivia under the 
name stolzmanni, for Parotani is on the high plateau and Charuplaya 
is almost or quite within the Amazonian forest. 
Oryzomys chaparensis sp. nov. 
Type from Todos Santos, Chaparé River, Bolivia. Altitude about 
1200 feet. No. 21,330 Field Museum of Natural History. Adult male. 
Collected March 15, 1915 by R. H. Becker. 
Characters. A species of medium size with the tail slightly longer 
than the head and body, the pelage rather short, and the throat and 
inguinal region with self-colored hairs; mammz (in one specimen) 
I—2=6. 
Color. Upper parts ochraceous buff liberally mixed with dusky 
lines, producing a general effect approaching wood brown or Isabella 
color; head, face, and sides practically like back; ears dusky outside, 
cinnamon inside; a poorly defined line of ochraceous buff between the 
color of the upper parts and the under parts; feet white; outer side of 
tarsal joint broadly and distinctly marked with brownish; tail finely 
scaly and except upon close examination appearing naked, dusky above 
and for its distal third below, whitish for its proximal two-thirds below; 
under parts creamy, the hairs of the belly and breast with dark bases, 
those of the throat and inguinal regions and the median part of the 
inner sides of the legs self-colored. 
Skull. Skull relatively long and slender; interorbital region rather 
narrow and elevated, the anterior half of the frontals being distinctly 
higher than the posterior; supraorbital edges sharp and elevated but not 
beaded; nasals broad and with considerable median depression poste- 
riorly; zygomatic plate broad, convex in front; palatine foramina short 
*Ann. & Mag. Nat. Hist., (7), IX, p. 130, 1902. 
