nerv Akoclonyrom Tierra del Fuego. 497 



Akodon francei, sp. n. 



A dark-coloured species of the long-skulled A. longipilis 

 group. Size rather less than in A. longipilis. Fur close 

 and fine, not excessively long considering that the specimen 

 is a winter one from the far south ; hairs of back about 

 10-11 mm. in length. General colour above slaty grey 

 (grey no. 4 of Ridgway), the middle dorsal area slightly 

 tinged with buffy, owing to the hairs having very narrow 

 subterminal buffy bands on them. In the allied species 

 A. longipilis, hirtus, and suffusus the bands are much 

 broader and the general colour of the whole upper surface is 

 therefore more stronglv huffy. Head, neck, and sides nearly 

 pure slaty grey. Under surface white, the hairs slaty 

 basally, with white tips, the line of demarcation on sides high 

 up and rather sharply defined, so as to give a strongly bicolor 

 aspect to the whole animal. Ears brown. Hands and feet 

 pure white ; claws of normal proportions, not elongate 1 as in 

 Chelemys. Tail thickly hairy, conspicuously bicolor, sharply 

 defined blackish above, white below. 



Skull in general proportions very similar to that of 

 A. suffusus, but rather larger and with a longer brain-case. 

 Outer plate of anteorbital foramen rather broader. Supra- 

 orbital edges similarly rounded ; interparietal minute. 



Dimensions of the type (measured by Mr. Wolffsohn before 

 skinning, on the specimen preserved in brine) : — 



Head and body 116 mm. (probably more in the flesh) ; 

 tail 80 ; hind foot 24 ; ear 13. 



Skull : greatest length 30"3 ; basilar length 23 ; zygo- 

 matic breadth 13'6 ; nasals 11*5 ; interorbital breadth 5*2 ; 

 brain-case breadth 12*5 ; diastema 8 ; palatal foramina 6*4 ; 

 length of upper molar series 4*1. 



Nab. Santa Maria, Tierra del Fuego. 



Type. Adult male. B.M. no. 8.11.19.1. Original 

 number 283. Collected 26th August, 1908, by Dr. France. 

 Presented by J. A. Wolffsohn, Esq. 



This very striking species, which I have had much pleasure 

 in naming after its discoverer, Dr. France, is at once recog- 

 nizable by its dark olivaceous-grey colour, which contrasts 

 with its white belly and snowy-white feet, all the other three 

 species of the group being of a much paler grey, broadly 

 suffused with buffy. It is most nearly allied to A. suffusus, 

 wliich is similarly bicolor, but far less strongly contrasted, 

 and is no doubt the latter's representative on the south side 

 of the Straits of Magellan. 



