76 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



canescens. The other is mistakably identified as the type of A. xantho- 

 rhinus, as already noted under that species. 



Akodon canescens is closely related to A. arenicola (Waterhouse), 

 based on specimens from Maldonaldo, at the mouth of the La Plata, but 

 it differs from it in smaller size, more grayish coloration, and yellowish 

 muzzle. Two specimens collected by Mr. Durnford at Chubut are referred 

 by Mr. Thomas (/. c.) to this species. Mr. Durnford, in his field notes 

 published by Mr. Thomas, says it is "common in straw-heaps and grana- 

 ries," and that it "burrows in the ground, or more usually takes posses- 

 sion of some of the numerous cracks which may always be found in the 

 earth, and appropriates them for its home. It has five or six young at a 

 birth." 



Akodon suffusus Thomas. 



(Plates XI, Fig. 5, Skull ; XII, Figs. 9 and 10, Teeth.) 



? Hesperomys {Habrothrix) longipilis Milne-Edwards, Miss. Scient. du 



Cap Horn, VI, Z06I., Mamm., 1890, 28, pi. v, fig. 2, animal. "Santa 



Cruz de Patagonie." 



Acodon siiffitsus Thomas, Ann. and Mag. Nat. Hist. (7), XII, Aug., 1903, 



241. " Valle del Lago Blanco, Southern Chubut (Cordillera region)." 



Median upper surface, from between the eyes to base of tail, dark dull 

 reddish brown ; sides of head and body gray, passing gradually into the 

 reddish brown of the back and into the grayish white of the ventral sur- 

 face, which extends unusually high up on the sides of the body and 

 cheeks ; ventral surface white or grayish white, the pelage plumbeous at 

 the base, in some specimens wholly concealed by the long white tips of 

 the hairs ; facial region anterior to the eyes gray like the sides of the body 

 with a faint tinge of brown ; ears covered with very short brownish hairs 

 externally, nearly naked internally; tail bicolor, reddish brown above, 

 whitish below, heavily clothed with short hairs ; fore feet dingy soiled 

 yellowish gray above, palms naked, flesh color ; hind feet soiled whitish, 

 soles naked, dusky brown. 



Measurements. — Average and extreme measurements of 13 males: 

 Total length, 170 mm. (165-178); tail vertebrae, 70 (65-74); hind foot, 

 25 (25~26). The females are, slightly larger, 8 females measuring as 

 follows: Total length, 176.6 (170-188) ; tail vertebrae, 71.8; hind foot, 25. 



An average adult skull measures as follows : Total length, 30 ; basal 

 length, 25 ; length of nasals, 1 1 ; palatal length, 1 2 ; palatal foramina, 



