154 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. X. 



constant characters separate them beyond dispute without considering 

 the very marked cranial differences. 



Sciurus tricolor Poppig. 



Two specimens: Lagunas, Lower Huallaga River (i), Puerto 

 Arturo, near Yurimaguas (i). 



These specimens, especially the one from Lagunas, come from very 

 near Poppig's type locality. They show an important variation in the 

 color of the under parts, one being white throughout, except on the 

 chin, and the other wholly rich orange rufous. The skulls, as noted by 

 Thomas,* have very long narrow muzzles. This is accompanied by a 

 greatly compressed mandible and extraordinarily broad thin lower 

 incisors. These measure 5.5 mm. in depth and 24 mm. in length of 

 exposed front surface, dimensions which exceed those of any other 

 squirrel known to me. 



Mus musculus Linnaeus. HOUSE MOUSE. 



House mice are common in and about the coast towns. Two speci- 

 mens from Pacasmayo were preserved. 



Epimys alexandrinus (Geoffrey). ROOF RAT. 



After sporadic and poorly executed attempts to destroy them, rats 

 are still abundant in the coast towns of Salaverry, Trujillo, and Pacas- 

 mayo. The feeling that they are dangerous to the health of the com- 

 munity is growing, however, and the more intelligent people are more 

 and more inclined to make some effort to prevent their spread and in- 

 crease. Apparently they have not penetrated far into the highlands, 

 for we received no reports of them after leaving the coast until we 

 reached Yurimaguas, where we again found them numerous. 



Oryzomys stolzmanni Thomas. STOLZMANN'S ORYZOMYS. 



Forty-one specimens: Mountains east of Balsas (i), Tambo Almi- 

 rante, near Uchco (8), Moyobamba (32). 



Huambo, the type locality of Oryzomys stolzmanni, is less than 50 

 miles directly south of Tambo Almirante, on the same slope of the 

 mountains, and at nearly the same altitude. Moreover, the local 

 conditions are much alike at the two places, the forest dense, and the 



* Ann. & Mag. Nat. Hist. (7), VI, p. 138, July, 1900. 



