NO. 2333. MAMMALIA COLLECTED IN PERU BY HELLER— THOMAS. 227 



Head and body, 128; tail, 132; hindfoot (with claws), 36 (34 with- 

 out claws on the dried skin). The hindfoot of No. 194917 measures 

 36 mm. (without claws) , dried. Skull of type (immature) ; greatest 

 length, 34 ; condylo-incisive length, 31 ; nasals, 14 ; palatilar length, 

 29 ; palatal foramina, 6.2 ; upper molar series, 7.2. 



Type.— Immature female, from Santa Ana, U.S.N.M. No. 194915. 

 Original No. 581. Collected December 22, 1914, by E. C. Erdis. 



Specimens examined.— Ma\Q. and two females from Santa Ana, 

 3,480 feet (Nos. 194917, 194915, 194919). 



While a half-gTown Holochilus from the Ucayali at the mouth of 

 the Pachitea (alt. 440 feet), collected by Garlepp in 1903, is so ex- 

 actly like equally immature specimens of H. sciureus that I see no 

 reason to distinguish it, these specimens, from altitudes over 3,000 

 feet, are so uniformly without the marked wash of buffy on the 

 flanks characteristic of that animal that they should apparently have 

 a special name. 



Unfortunately the material is somewhat imperfect, as neither 

 194917 nor 194919 has a skull, while the type is decidedly immature. 



The Pachitea specimen, like those of the lower Amazon, has a well- 

 marked bufl'y wash along the flanks, and it is not improbable that 

 from Peru, at a comparatively low altitude, right down the Amazon 

 to Para and Pernambuco, only one species of the genus is found, a 

 distribution not impossible in so water-loving an animal. I confess 

 now to considerable doubt as to whether E. guianae ought to have 

 been separated from 11. sciureus— a doubt which also applies to 

 H. amazonicus. 



The N. Peruvian Holochilus obtained by Mr. Osgood in 1912, also 

 immature, is presumably the same as that from Pachitea. 



27. NECTOMYS GARLEPPI Thomas. 



Fifteen specimens, as follows: 



Rio Comberciato, 2,100 feet, 1 (No. 194830). 



Eio Cosireni, 3,000 feet, 1 (No. 194831). 



Eio San Miguel, 4,500 feet, 3 (Nos. 194832, 194834-5). 



Santa Ana, 6 skins (Nos. 194906-11) and 4 in alcohol (Nos. 195111- 

 14). 



The single adult specimen of this series. No. 194830, is somewhat 

 intermediate between N. garleppi and the North Peruvian N. apicalk 

 Peters. I provisionally apply to it the name which is geographically 

 most pertinent. 



28. ORYZOMYS KEAYSI Allen. 



Thirteen specimens, as follows: 



Machu Picchu, 6,000 feet, 11 (Nos. 194550, 194553, 194556, 194558- 

 60, 194562-3, 195108-9). 



Paltaybamba, 5.000 feet, 1 (No. 194883). 

 Santa Ana, 3,480 feet 1 (No. 195093). 



