• j'i'oin Xinth-icrst rn P<UaijJuii. 20 5 



Dincnsions of the type : — 



Head anil body 87 mm. ; tail 79; IiitiJ foot 22 ; ear 15. 



Skull: ^ifiitest lentj;tli 25*7; coiiilylo-iiicisivo lenj^tli 2'\ ', 

 zyt^omatic lnea 1th 12*() ; nasuls 9*8 ; iiitcrorhit il l)ieailtli 4' I ; 

 hreailih of brain-case 12 ; p.ilatilar lt;n;4th 10 ; palatal fora- 

 mina. (> ; post-loraminal palate !V2 ; upper molar series 3'7. 



//(i/>. a>« above. 



Tiifie. Youtifjftdult main. H.M. no. 19. I. l.iil. Oiii^anal 

 nunil)er 108. Collected 26th February, 1918. 



Tld?* appears to be the most southern of the widely aprftad 

 olivareus-arenicolii group, whicli ran;^es tVom here northwards 

 to F^cuador, and the members of which are the most common 

 field-mice in ahnost every locality, takiuLij the place in nature 

 of our common voles. The other species obtained by 

 Sr. Budin are of the more southern xrinthorJiinns-canescenx 

 grou[), distinguished among other things by the much shorter 

 tail. 



\^Akodon iniscatus, sp. n. 



Size and proportions as in A. .rant/ior/nnn.i, but skull more 

 bowed and thickly built, with shorter muzzle. First molar 

 with a deep and distinct anterior notch, which only wears oHf 

 in old age. A white patch on the chin. 



Colour of typical race coarsely lined brown, near Ridgway's 

 " biiffy brown." 



Dimensions of the type : — 



Head and body 92 mm. ; tail r)3 ; hind foot 10 ; ear 11. 



tSkuU : greatest l(Migtli 23*7; condylo-incisive length 21*7; 

 zyjjomatic breadth 12'4: ; interorbital breadth 4; breadth of 

 brain-case 11 ; palatal foramina 5'4 ; upper molar series 3*5. 



I/ub. Southern Buenos Ayres Province southwards into 

 Pata;::onia. 'I'vpo from the Vallo de Lago Blanco, Koslowsky 

 region, Patagonia, 40° S. Other .specimens from Peru Station, 

 N.W. of Baliia Blanca, Chuijut, and Port Desire, besides the 

 Budin examples referred to b'dow. 



Type. Adult female. B.M. no. 3. 7. 9. G4. Original 

 number XXX. Collected 2Gth April, 1900, by J. Koslowsky. 

 Ten specimens examined. 



Our knowledge of the small Akodons of Patagonia has 

 been in a very confused condition, though an improvement 

 was ma<le by Dr. Allen, who corrected certain mistakes that 

 had been made in the labelling of the Darwin specimens, on 

 which th'ir nnmenclature hangs. He rightly fixed on 

 Ii.]\I. no. 55. 12. 24. 157 as tho primary type of A. canescens, 

 Waterh., and 55. 12. 24. 150 of A. .vanthorhinus, VVaterh., 



