the Species of the Genus Ciivia. 155 



Skull: greatest upper length 62; condylo-incisive length 

 58; zygoniutic breadth 35; nasals .19*7 X 8*5; interorbital 

 breadth 12"6; breadth of parietals across brain-case 24*5 ; 

 diastema 17'4; bulla; 12-2 X 9*3; upper tooth-series 14'6. 



Hub. Serra do Mar, Eastern Parana. Type from Roga 

 Kovn. Alt. 1000 m. 



7)/pe. Adult female. B.M. no. 3. 7. 1. 96. Original 

 number 831. Collected 6th September, 1901, by Alphonse 

 Robert. Six specimens. 



Tliis cavy of the Serra do Mar is readily distin.cuishable 

 from C. aperea by its dark colour, blackish back, butfy belly, 

 reciuced chest-markings, and by the short and slender 

 muzzle of its skull. In the lowlands of the same region, at 

 Morretes (10 m.), M. Robert found a representative of the 

 C. fu'gida group. 



Next comes the "well-known quiso of the Argentine and 

 Uruguay :— 



Cavia pamparum, Thos. 



Cavia rufescens iiamiiarujn, Thos. Ann. & Mag. Nat. Hist. (7j viii. 

 p. 538 (1901j. 



Allied to C. aperfa, but smaller j the skull usually about 

 62-63 mm. in length when adult. Colour as in aperea, but 

 distinctly more greyish or olivaceous, less brown. Under 

 surface whitish or slightly drabby, the chest-pattern well 

 marked. 



Skull shaped as in aperea, but smaller ; the muzzle of the 

 same general proportion, not reduced as in C. rosida. 



Range from Corrientes and Uruguay southwards to 

 Soiithtrn Buenos Ayres. Specimens in Museum from "20 

 miles north of Corrientes^' {2'urner Hendtrson) ; Goya, 

 Corrientes {li. Perrens) ; Miildonado {Darivin) ; La Plata 

 [Thomas); Los Yngleses, Ajo, Buenos Ayres {E. Gibson)-, 

 and Bonifacio, S.W. Buenos Ayres (ii. Keiup). 



All the specimens from the above considerable range agree 

 very closely with each other in size and colour, no geogra- 

 ]ihic!il variation being observable. Two of Mr. Gibson^s Aj6 

 specimens, however, out of seven are abnormally larger than 

 tlie otlicrs, with decidedly larger skulls; but these appear 

 more or less diseased, and it is possible that tiiey represent au 

 infusion of domestic guinea-pig blood, although there is no 

 colour indication of this. The other specimens of the same 

 lot are quite like the ordinary quiso. The size of the bulla 

 is a little variable, two of the Bonifacio series having this 

 12-1 and 11 mm. in length, that of the type being 11-7. 



