NO. 2333. MAMMALIA COLLECTED IN PERU BY HELLER— THOMAS. 23S 

 38. THOMASOMYS AUREUS Tomes. 



Five specimens, as follows : 



Torontoy, 9,000-10,000 feet, 4 (Nos. 194817-20). 



Ocobamba Valley, 9,100 feet, 1 (No. 194826). 



The identity of these specimens with average examples of the 

 somewhat variable T. aureus of Ecuador is remarkable. Compared 

 with a number of specimens from the neighborhood of Pichincha 

 they at first seem different by their more buffy belly; but not only 

 do two examples among the Pichincha series have the same buffy 

 belly, while two others are intermediate, but it is also of the same 

 deep buffy in the type, which came from Gualaquiza. 



The hind feet are more prominently particolored in the Torontoy 

 set, less so in the specbnen from Ocobamba, which closely matches 

 some of the Pichincha series. 



The majority of our Pichincha set are from about 7,000 feet, but 

 one is from 12,000 feet, consequently a topotype of Allen's T. a.- 

 altorum^ as to the validity of whose distinction from T. aureus I am 

 most doubtful. 



39. THOMASOMYS NOTATUS Thomas. 



1917. Thomasomys notatiis Thomas, Smiths. Misc. Coll., vol. 68, No. 4, 

 p. 2, April 10, 1917. 



A medium-sized species with a dark dorsal stripe, broad 'feet, and 

 well-marked metatarsal patches. 



Size far smaller than in T. aureus, almost as in cinereus. Fur 

 close, thick, rather woolly ; hairs of back 6-7 mm. in length. General 

 color above, in adults, ochraceous tawny, darker than the color so 

 named in Ridgway ; grayer on head, more tawny posteriorly ; an ill- 

 defined blackish streak down the middle of the back, from withers to 

 rump, varying much in distinctness, but always perceptible. Under- 

 surface soiled whitish, the hairs slaty basally, dull whitish termi- 

 nally ; lips and throat completely white, the hairs white to their bases. 

 Hands above silvery whitish without darker markings on metacar- 

 pals ; feet, on the other hand, only white along the edges and on the 

 digits; the tarsus and metatarsus broadly and prominently brown. 

 The feet themselves unusualh^ broad for a Thamasomys, more as in 

 Rhipidomys. Tail hairy, slightly penciled, uniformly dark brown 

 above and below. 



SImll (pi. 14, fig. 4) in general build like that of a miniature 

 T. aureus, except that the zygomata are not so convergent for- 

 wards. Nasals narrow, their borders curiously sinuate, converging at 

 their middle and then again diverging (or at least remaining strictly 

 parallel) in their posterior third. Interorbital region narrow, its 

 edges slightly raised to form low supraorbital ridges, similar to, 

 though smaller than, those of T. aureus; the ridges scarcely extend- 



