PRELIMINARY DIAGNOSES OF NEW MAMMALS 

 OBTAINED BY THE YALE-NATIONAL 

 GEOGRAPHIC SOCIETY PERU- 

 VIAN EXPEDITION 



Bv OLDFIELD THOMAS. British Museum 



By arrangement with the authorities of the Yale-National Geo- 

 graphic Society Peruvian Expedition the United States National 

 Museum has submitted to me for working" out the very fine collec- 

 tion of mammals made by Mr. lulmund Heller during the year 191 5. 

 This material was obtained at localities lying between Lat. 12° 30' 

 and 13° 30' S., Long. 'J2° and 73° W., in the region of Cuzco, Peru. 

 The following" are i)reliminary diagnoses of the new forms. A full 

 account of the collection will be published in due course. 



. MICRORYZOMYS, subg. nov. of ORYZOMYS 



Teeth very small. Zygomatic plate not projected forwards. 

 Genotype. — Or\zo)n\s iiiiiiittiis Tomes. 



ORYZOMYS (MICRORYZOMYS) AURILLUS, sp. nov. 



Near Oryconiys dryas, but color duller and ears longer. 

 Head and body of type 83 mm. ; tail 134; hindfoot 22.5 ; ear 15.5. 

 Skull, greatest length 23.5. 

 Habitat. — Torontoy. 

 Type. — Female. U. S. Nat. Mus. No. 194795 ; original number 255. 



HESPEROMYS FRIDA, sp. nov. 



Large, with comparatively long tail. Supraorbital ridges little 

 divergent. 



Head and body of type 102 mm.; tail 91 ; hindfoot 19; ear 18. 

 Skull, greatest length 26.7. 



Habitat. — Chospyoc, 10,000 feet. 



Type. — Female. U. S. Nat. Mus. No. 194779; original number 96. 



HESPEROMYS CARILLUS MARCARUM, subsp. nov. 



Duller colored than true carillus; tail white above; soles more 

 hairy. 



Smithsonian Miscellaneous Collections, Vol. 68, No. 4 



