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NEW MAMMALS FROM BRAZIL AND PERU 
BY WILFRED H. OSGOOD 
Among mammals obtained by the Field Museum before its field 
work in South America was temporarily discontinued, are a few belong- 
ing to species or subspecies not as yet described and named. Eight of 
these, of which the status seems reasonably certain, are described below. 
Two new subgenera of rodents, the existence and relationships of which 
were discovered as a result of the recent growth of American collections 
of neotropical mammals, are also included. For the use of material 
for comparison I am indebted to Dr. J. A. Allen of the American Museum 
of Natural History, New York, Dr. Witmer Stone, Academy of Natural 
Sciences, Philadelphia, and Mr. Gerrit S. Miller Jr., U. S. National Mu- 
seum, Washington. 
Marmosa impavida neglecta subsp. nov. 
Type from Yurimaguas, Peru. Altitude 600 ft. No. 19636, Field 
Museum of Natural History. Adult female. Collected September 28, 
1912, by Malcolm P. Anderson. Original No. 55. 
Characters:— Similar to Marmosa impavida of central Peru but color 
of under parts buff instead of soiled whitish; upper parts somewhat 
paler, especially sides of face and interorbital region; front of hind legs 
dark brown instead of grayish. 
Color:— Upper parts in slightly worn pelage russet brown to cin- 
namon rufous; forehead and interorbital region pale cinnamon; black 
facial stripe and eye ring well marked, extending nearly to rhinarium; 
under parts entirely buff, the hairs of the sides of the belly normally 
with slaty bases, the others self-colored; short-haired part of lower 
leg dark brown on front and sides; tail uniformly dusky except for slight 
irregular light markings on under side. 
Skull:— Very slightly larger than in typical impavida and having 
somewhat smaller mastoid bullae; otherwise similar. 
Measurements:— Type and two adult paratypes, respectively, 
measured by the collector: Total length 320, 295, 295; head and body 
134, I19, 129; tail vertebrae 186, 176, 166; hind foot with claws 17, 18, 
187 
