On new Ar,ji>ntine Specicit of kVoiiow, 213 



XVII. — Tao nriv Ar./pnt''ne '^pficiea 0/ Akodon, 

 ]^y Oldfiicij) Thomas. 



(rnblislioil by perinissioii of tlie Trustet'.s of the Mriti.->li .Mu.ioiim.) 



I-)iriUN(} ilio woiking out of 8r. Budin'.s Pafa^oiiiin colleciioii 

 tlio two following s|)L'cies of A/codon li;ivo provoJ to need 

 dcsciiptiou : — 



Akodon neocenus, sp. 11. 



A sliap^gy grey species allied to A. varius of Bolivia, 

 Size and general appearance very ninch as in A. r irius, 

 Aviili the same loose and rather shaggy fur, which is, how- 

 ever, rather longer and thicker ; iiairs of back about IH— 

 14 mm. in length, intermixed with longer biistle-hairs 

 attaining 17 mm. General colour greyer than in varius, 

 with lo.ss bufFy, though the essential mixture of grey and 

 bufiy, varied by the dark tips to the hairs, is similar. Hands 

 and feet whitish. Tail rather long, well haired, blackish 

 above, whitish below. 



Skull with the nasils narrower and more tapering poste- 

 rioily than in A. varius. Sujjraorbital broad with squared 

 edgis. Postero-external corners of brain-case developed info 

 .sharp angle's, as viewed from above, this region b^ing 

 usually smoothly rounded ; but this may possibly hereafter 

 ))rove to be merely individual. Palatal foramina to the level 

 of the front edge of the middle lamina of m\ Bullaj decidedly 

 larger than in varius, their breadth in the type, taken at 

 right angles to the diagonal length, 4-3 mm. 



Incisors rather more proodont than in varius, the angle 78° 

 in two specimens as compared with 72°-75°. 



Dimensions of the type (measured on the spirit-speci- 

 men) : — 



Head and body 108 mm.; tail 85; hind foot 2'.V5 ; car 18. 



Skull: greatest len<;th 29*2; condylo-incisive length 28'2 ; 



zygomatic breadth 14*8 ; nasals 11x3-2; interorbital breadth 



5*2; breadth of brain-case 13 ; palatilar h-ngth 12*8; palatal 



I'oramina 7 ; upper molar series (worn) 4"8. 



Ifub. Ni'uquen, Uio Liinay, Uit|)er Rio Negro, Patagoiii.i. 

 'Ji/pe. Old mah; in spiril. B.M. no. 1 1 , 1 1. I'J. 1 2. Col- 

 lected by E. Weiske, 4ih Nove.nb r, I'JIO. Pre-enled 

 by the Hon. N. Charles R)lhscliill. An imperlect .-"kin, 

 No. 11. 11. 19. 10, also in eolleet.on. 



Ann.ti- .yag. i\. JJii,t. &iii.[K To/, iii. 15 



