156 Fretp Museum or Natura History — Zo6étocy, Vor. X. 
of braincase 11.4; post-palatal length 7.1; palatine foramina 4.4 x 1.7; 
upper toothrow 3.7. 
Remarks.— This form has approximately the color of O. arenalis 
with the size and cranial characters of O. stolzmannzt. 
Oryzomys arenalis Thomas. DESERT ORyzomys. 
Twenty-three specimens: Menocucho (9), Pacasmayo (11), Trujillo 
(3). 
This is one of the smallest known species of Oryzomys. It should be 
compared with Oryzomys peruvianus (Peale) from Callao when speci- 
mens of that species are obtained. It was found in relatively moist 
situations at the edge of small swamps or irrigating ditches. 
Oryzomys andinus sp. nov. 
Type from Hacienda Llagueda, upper Rio Chicama, Peru. Altitude 
6,000 ft. No. 19430 Field Museum of Natural History. Male adult. 
Collected March 12, 1912, by W. H. resol and M. P. Anderson. 
Orig. No. 4525. 
Characters.— A medium-sized Oram allied to O. stolzmannt, but 
having a much larger foot and a very long tail. Coloration of the 
normal oryzomyine type; upper parts pale ochraceous darkened by 
numerous fine dusky lines; a slight ochraceous lateral line; face and head 
somewhat grayish; under parts creamy white, sharply differentiated, 
the hairs with slaty bases; ears thinly haired with ochraceous basally 
and internally, with brownish distally and externally; feet white; tail 
thinly clothed with very short hairs, brownish above, whitish below 
for proximal half, gradually becoming dusky toward the tip. Skull 
similar in general form to that of O. stolzmanni but relatively narrower 
and with smaller teeth and audital bulle; palatine foramina much com- 
pressed; braincase angled and truncate rather than rounded behind; 
interorbital region and base of nasals slightly concave between sharply 
angled edges. 
Measurements.— Type: Total length 253; head and body 104; tail 
149; hind foot 26; ear from notch (dry) 16. Skull of type: Greatest 
length 26.4; basilar length 20; zygomatic breadth 14; mastoid breadth 
11; interorbital constriction 3.8; nasals 10 x 2.8; palatine foramina 4.8 x 
1.4; diastema 6.7; width of infraorbital plate 2.6; upper toothrow 3.4. 
Remarks.— If, as seems highly probable, specimens from Moyo- 
bamba and Tambo Almirante represent typical O. stolemannzt, it is plain 
