MAMMALS OF AN EXPEDITION ACROSS NORTHERN 



PERU. 



BY WILFRED H. OSGOOD. 



The zoological work of the Field Museum in South America in 1912 

 was largely confined to northern Peru which was crossed from west to 

 east by M. P. Anderson and myself during the months from January to 

 September. Approximately 2,000 specimens of mammals and birds 

 were collected including a gratifying number that fulfill in an important 

 way the objects of the expedition. 



Some of the larger mammals, as the Spectacled Bear and the White- 

 lipped Peccary, already have been prepared for exhibition, while other 

 material serves to complete the necessities for certain large habitat 

 groups previously planned. The collection of mammals proves to 

 contain sixteen species and subspecies new to science 1 as well as many 

 species and no less than twelve genera new to Field Museum including 

 some, as Mesomys and Amorphochilus, which may fairly be called great 

 rarities. 



The following account of the mammals obtained by the expedition 

 has been abbreviated by circumstances which have made it necessary 

 to omit certain illustrations and discussion of problems of geographic 

 distribution. As a contribution to the scanty knowledge of the mam- 

 mals of the region, however, it seems advisable to publish the list in 

 its present form with introductory matter reduced to a brief description 

 of localities. 



Although somewhat less so than formerly, it is still necessary in 

 classifying neotropical mammals to consult, either directly or vicari- 

 ously, the collections of the British Museum. It is with the utmost 

 gratitude, therefore, that I acknowledge the continued assistance of 

 Mr. Oldfield Thomas who has made numerous comparisons for me with 

 species not possessed by any American museum. Thanks are extended 



1 Nine of the new forms have been described in a preliminary paper (Field Mus. 

 Nat. Hist., Pub. 168, Zool. Ser., X, pp. 93-100, May 31, 1913); a tenth was named 

 in a monographic revision by G. S. Miller (Proc. U. S. Nat. Mus., XLVI, pp. 413- 

 416, Dec. 31, 1913); and six are described in the present paper. 



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