APRIL, 1914. MAMMALS OF NORTHERN PERU OSGOOD 149 



Metachirus andersoni Osgood. 



Three specimens were obtained by Mr. Anderson near the Parana- 

 pura River about eight miles from Yurimaguas. As indicated by its 

 dark rich coloration, the species inhabits heavy forest. 



Metachirus nudicaudatus tschudii Allen. 



One specimen, an immature female, was caught in a banana grove 

 in Moyobamba. It is much darker above than an adult from Chan- 

 chamayo, Peru, but the under parts are more whitish. A dark blackish 

 line runs from the forehead to the middle of the back and less distinctly 

 thence to the base of the tail. It may be referred to M. tsckudii of 

 Allen since it agrees closely with the description of that form and has 

 the blackish median line well marked. This character, however, may 

 be a mark of immaturity. 



Marmosa impavida (Tschudi). 



Three specimens, Yurimaguas. 



The long narrow skull of this species with its slightly beaded and 

 nearly parallel-sided supraorbital edges is very distinctive, but for 

 greater certainty a specimen was submitted to Mr. Thomas who con- 

 firmed the identification. In size and color of upper parts, M . impavida 

 is not greatly different from M. musicola but cranially there are marked 

 distinctions. There is some variation in the color of the under parts, 

 one specimen having the entire lower surface creamy buff to the roots 

 of the hairs, while the other two have a lateral area in which the hairs 

 have slaty bases as described for impavida. 



Marmosa madescens Osgood. 



Four specimens: Tambo Almirante, near Uchco (i), Poco Tambo 

 (i), Tambo Ventija, near Molinopampa (i), Moyobamba (i). 



This pretty little opossum inhabits the densest forests of the upper 

 montagna occupying a belt extending from 2,500 feet altitude up to 

 8,000 feet. Its range appears to meet that of M. musicola at Moyo- 

 bamba where both species were taken but their local habitats are 

 different, that of madescens being the forest and that of musicola the 

 open fields and cultivated areas. M. madescens is the darkest Marmosa 

 known to me. Apparently the only species that approach it in this 

 respect are M.fuscata of the Sierra de Merida, M. ph&a of S. W. Colom- 

 bia, and M. sobrina of Ecuador. Judged by the description, M. sobrina 

 is somewhat doubtfully distinct from madescens. 



