160 FIELD MUSEUM or NATURAL HISTORY ZOOLOGY, VOL. X. 



birds and other animals, as, for example, the peculiar thrush Plane sticus 

 maranonicus. The discovery of such distinct types emphasizes the 

 great imperfection of our knowledge not only of the causes but of the 

 facts of vertebrate distribution in the Andes. 



Owing to lack of horsefeed, it was not possible for us to stop at Tambo 

 Carrizal more than one night, and we were fortunate in securing these 

 rats in and about the old tambo itself. 



Nectomys fulvinus Thomas. WATER RAT. 



Six specimens: Lagunas (3), Yurimaguas (3). 



For these very dark richly colored water rats the name fulvinus is 

 perhaps as suitable as any other. Without typical specimens of 

 N. rattus of the upper Rio Negro and without a definite type locality for 

 N. fulvinus, nothing more than a provisional identification can be made. 

 It is reasonably certain, however, that N. fulvinus was not from Quito, 

 as thought possible when it was named, since another species, N. 

 saturatus, inhabits that region. Our specimens from the Huallaga 

 River increase the probability that fulvinus came from well east of 

 Quito. There is considerable color resemblance to N. melanius of 

 Guiana, a species not known at the time fulvinus was described, so 

 perhaps Guiana as the source of fulvinus, a possibility originally dis- 

 missed, may need reconsideration. 



Neacomys spinosus Thomas. SPINY MOUSE. 



Four specimens: Moyobamba (i), Poco Tambo (2), Yurimaguas (i). 



Apparently rather rare, this species was only obtained after much 

 trapping in heavy humid forest, where it was found under rocks and 

 logs. The color of the under parts varies from nearly pure white to 

 ochraceous buff, and the belly hairs in some specimens are white to the 

 roots and in others with slaty bases of varying width. 



Rhipidomys latimanus Tomes. 



Two specimens from Moyobamba are referred to R. latimanus by 

 Mr. Thomas. They were obtained in houses in the town. The color 

 is much paler than usual in this genus, the upper parts being a light 

 wood brown tinged with fawn. The type of this species is credited to 

 Pallatanga, in western Ecuador, a locality rather removed from Moyo- 

 bamba, and it is possible that the original describer may have been 

 misinformed regarding the source. 



