216 Mr. O. Thomas on some small 



readily presumed that specimens from one end of the district 

 are distinct as a matter of course from those described from 

 the other — a presumption which, allowing for the great 

 difference in altitude and position, would in other parts of 

 America generally be quite justifiable. 



4. Akodon Spegazzinii, sp. n. 



a, h. Lower Gachi. 

 c. Pampa Grande. 



A medium-sized Akodon of a generally fulvous colour, 

 above and below. 



Size rather smaller than A. olivaceus. Fur fairly long, 

 soft and woolly ; the underfur about 10 mm. long on the back. 

 General colour dull grizzled fulvous rufous, quite unlike that 

 of the greyish Akodons of the olivaceus group. Longer hairs 

 as usual black. Fulvous body-colour clearer on sides, and 

 passing almost unaltered on to the belly, which is scarcely 

 lighter than the flanks ; hairs round the anal region brighter 

 fulvous. Throughout, above and below, the basal three 

 fourths of the hairs are dark slate-coloured. Ears fairly 

 large, rounded, laid forward in a spirit-specimen they reach 

 about 2 raillim. short of the posterior canthus ; well clothed 

 with short fulvous hairs. Hands and feet pale whitish 

 fulvous above; claws long and strong, but not exaggerated as 

 * in the A. megalonyx group. Palms and soles naked, with the 

 pads 5-6 as usual ; fifth hind toe without claw reaching to 

 the end of the first phalanx of the fourth. Mammae 2 — 2 = 8. 

 Tail rather long for an Akodon, finely haired, blackish above, 

 yellowish white on the sides and below. 



Skull strongly built, though the zygomata are not very 

 widely expanded. Nasals long, rather narrow. Literorbital 

 region smooth, slightly convex, its edges square but not 

 ridged. Interparietal very small, narrow from before back- 

 wards, almost as broad laterally as in the middle line. 

 Palatine foramina large and open, reaching backwards past 

 the middle of m^. Posterior narial fossa narrow, the palatal 

 edge nearly a millimetre behind w'^ 



Incisors dark orange above, pale yellowish below. Molars 

 strictly Akodont. 



Dimensions of the type, measured in spirit before skinning 

 (female) : — 



Lead and body 92 millim. ; tail 71; hind foot, without 

 claws, 20 ; ears 14. ('J'he inclusion of the claws would increase 

 the hind foot measurement by about 2*5 millim.) 



Skull: basal length ^'I'b, basilar length from henselion 

 20*5; nasals 9"6x3; interorbital breadth 4"0 ; interparietal 

 7xl"4; palate length from henselion 11*3 j diastema 7'2; 



