small Mammals from Salta and Jujuy. 189 



Size about as in varius. General colour above mixed 

 blackish and buffy, the resulting combination near " butty 

 brown/'' the lining rather well marked, the head greyer, the 

 rump more buffy. Sides and belly distinctly more huffy, 

 the ends of the hairs on lower sides and below strong 

 cinnamon-buff ; the chin and interramia prominently 

 contrasted white. Ears about the colour of the head. 

 Claws rather long, especially anteriorly, as usual in the 

 obscurus group, the front claw both in front and behind 

 4 mm. in length, the posterior therefore not exceeding the 

 anterior. 



Skull on the whole very like that of A. obscurus, of the 

 same stout heavy build, with squared but not ridged inter- 

 orbital region, and minute interparietal. Palatal foramina 

 long, reaching to the level of the second lamina of m 1 . 



Incisors even more proodont * than in A. obscurus, their 

 angle with the tooth-row 95° in the type, specimens of 

 obsciwus ranging from 85° to 92°. Their front surface 

 in the type unusually light coloured, pale yellow, lightening 

 to white at the tips. Molars as in A. obscurus. 



Dimensions of the type (measured in the flesh) : — 

 Head and body 101 mm. ; tail 67 ; hind foot 22 ; ear 16. 

 Skull : greatest length 27'2 ; condylo-incisive length 27 ; 

 greatest breadth 15*5 ; nasals 9 ; interorbital breadth 5 ; 

 breadth of brain-case 12'3 ; palatilar length 13; palatal 

 foramina 6'6 ; upper molar series 5. 

 Hub. and Type as above. 



This is a very well marked species, differing widely in 

 colour from the other members of the A. obscurus group, 

 to which the characters of its skull seem to ally it. In 

 external appearance it is not unlike A. varius and simulator, 

 apart from the prominent buffy colour of its lower surface. 

 Its contrasted white chin is just as in simulator. 



8. Akodon puer camosus, subsp. n. 



cJ. 22; ? . 21, 33. Leon, Jujuy, 1500 m. 



Agreeing with true A. puer in general characters and in the 

 remarkably small size of the teeth, but the colour is darker 

 and duller, less suffused with buffy or tawny. Dorsal surface 

 dark olivaceous, near "brownish olive"; sides but little 

 more buffy. Under surface not sharply defined, terminal 

 half of hairs dull " pinkish buff." 



* Cf. Ann. & Mag. Nat. Hist. (9) i. p. 35 (footnote) (Jan. 1918). 



