5. 2333. MAMMALIA COLLECTED IN PERU BY HELLER— THOMAS. 231 



Dimensions of the type : Head and body, 102 mm. ; tail, 91 ; hind- 

 foot, 19 ; ear, 18. Skull, greatest length 26.7 ; condylo-incisive length, 

 24.3; zygomatic breadth, 14; nasals, 10.7; interorbital breadth, 3.8; 

 breadth of braincase, 11.6 ; zygomatic plate, 3 ; palatilar length, 11.2 ; 

 palatal foramina, 5.7 ; upper molar series, 3.9. 



Type.— Adult female from Chospyoc, U.S.N.M. No. 194779. 

 Original No. 96. Collected April 14, 1915. 



Nineteen specimens, as follows: 



Huaracondo. 11,000 feet, 6 (Nos. 194715, 194770, 194772, 194775-6). 



■Chospyoc, 10,000 feet, 8 (Nos. 194719, 194726, 194773, 194779-82). 



Torontoy, 8,000 feet 1 (No. 194690). 



Querafrata, 11,400 feet, 3 (Nos. 194710-11, 194723). 



[Anta, Cuzco, 1, B. M. No. 3.2.9.10, O. Garlepp.] 



This species differs strikingly from the other equal-sized species 

 of restricted Hesperomys by the Phyllotis-like build of its interor- 

 bital region, the edges of which are symmetrically concave, and with- 

 out the broadly divergent ridges found in H. venustus and its allies, 

 and also in Graomys. From Phyllotis it is distinguished by its 

 absolutely brachyodont molars, these being semihypsodont in that 

 genus. When writing recently on this subject I erroneously spoke 

 of the teeth of Phyllotis as brachyodont— a mistake induced by their 

 less hypsodontism as compared with those of Euneomys. But they 

 are very markedly more hypsodont than in Hesperomys^ this being 

 the real essential difference between the two genera. 



35. HESPEROMYS CARILLUS MARCARUM Thomas. 



:1917. Hesperomys carillus inarcarum Thomas, Smiths. Misc. Coll., vol. 68, 

 No. 4, p. 1. April 10, 1917. 



Very similar to H. carillus of the Yungas region of Bolivia, but 

 -distinguished (1) by the general color being duller and grayer, with 

 less buffy infusion; (2) by the upper side of the tail being, like the 

 sides and below, quite white instead of more grayish buffy; and (3) 

 by the palms and soles being considerably more hairy. In true 

 caHllus the soles, along their middle line at least, are naked almost 

 to the heels, while in all the five available specimens of marcarum^ 

 taken at different seasons, the soles are hidden by the hairs to the 

 level of the fifth or sixth sole pad. 



Dimensions of the type, measured on skin: Head and body 

 (stretched), 82; tail, 46; hindfoot, 17.7. Skull— nasals, 9; interor- 

 bital breadtli^ 3.9; palatilar length, 9.2; palatal foramina, 5; upper 

 molar series, 3.7. 



Type: Adult skin from Lauramarca, B. M. No. 3.2.9.8. Original 

 No. 464. Collected June 25, 1899 by O. Garlepp. Presented by 

 Oldfield Thomas. 



