APRIL, 1914. MAMMALS OF NORTHERN PERU OSGOOD 155 



climate humid.* The probability is great, therefore, that our speci- 

 mens from Tambo Almirante represent true O. stolzmanni, and since 

 the type is imperfect and not fairly comparable with modern specimens, 

 it becomes practically necessary to regard them as that species. A 

 large series from Moyobamba seems referable to the same species, 

 although averaging paler and including some specimens with somewhat 

 whitish under parts. This paleness is perhaps ontogenetic and may 

 be due to the fact that nearly all the specimens from Moyobamba were 

 taken about houses and gardens in the town rather than in the adjoin- 

 ing forest. The published measurements of the type of stolzmanni 

 indicate an animal slightly larger than the average in our series, but 

 there is at least one unusually large example among those from Moyo- 

 bamba which nearly equals it. 



The specimens from Tambo Almirante have clear ochraceous buff 

 under parts, lighter toward the chin. The upper parts are somewhat 

 darker and with many fine lines of dusky. Average measurements of 

 four adults are: Total length 214 (205-224) ; head and body 94 (91-96) ; 

 tail 120 (111-128); hind foot 23.9 (23.5-24.5). 



Oryzomys stolzmanni maranonicus subsp. nov. 



Type from Hacienda Limon, near Balsas, Maranon River, Peru. 

 No. 19449 Field Museum of Natural History. Male adult. Collected 

 May 7, 1912, by W. H. Osgood and M. P. Anderson. 



Characters. Similar to Oryzomys stolzmanni but paler and having 

 nearly white under parts sharply distinguished from the upper parts. 

 Ground color of upper parts nearly ochraceous with a fine linear mixture 

 of dusky; sides more nearly pure ochraceous; head and face scarcely 

 different from body; under parts soiled whitish, sharply defined, the 

 hairs with slaty bases; feet white; tail above dusky, below whitish for 

 the proximal half, and thence gradually darker to the tip. 



Skull practically as in stolzmanni, although in the type the brain- 

 case is deeper and more arched. 



Measurements. Type: Total length 215; head and body 92; tail 

 123; hind foot 24; ear from notch (dry) 14. Skull of type: Basilar 

 length 17.4; zygomatic width 12.6; interorbital constriction 3.8; width 



*The following description of Huambo, from Stolzmann's notes, is given by 

 Taczanowski (P. Z. S., p. 4, 1882): "Huambo. 3,700 pieds de altitude. Plantation 

 inhabited au fond de la for^t vierge, a 10 kilometres de Chirimoto, au bord de la 

 riviere Huambo, qui, comme on le pretend, se rend pres de Pachiza au fleuve de 

 Huallaga. C'estune foret chaude et humide, du caractere des forts vierges." 



