On Cavies of the Genus Caviella. 445 
LIV.—On Caries of the Genus Caviella. 
By OLpFieLp Tuomas. 
(Published by permission of the Trustees of the British Museum.) 
Durine his work in Argentina Sr. Budin has obtained a 
considerable number of cavies belonging to the genus Caviellu, 
some from N.W. Patagonia, but the majority from Catamarca 
and San Juan—a region whence the genus had only been 
previously represented by the type of C. menas. 
In distribution these animals form a more or less continuous 
series from Catamarea in the north to Southern Patagonia, a 
distance of some 1500 miles, from 28° 8. to 50° S., all along 
the eastern edge of the Andes, and extending eastward to the 
sea at the Rio Negro and southwards. 
On trying to sort the material availabie, it appears that 
five geographical forms may be distinguished, whose characters 
are mainly those of the skull. But these vary in each group 
enough to overlap those of the next, so that it seems to me 
that the proper course is to treat the whole as one species, 
with five geographical subspecies, which may be defined as 
follows :— 
Caviella australis australis, Geoff. & d’Orb. 
Syn. Kerodon kingit, Benn. 
Size smallest. Colour more or less olivaceous. 
Skull with the muzzle short, sharply contracted anteriorly, 
the nasals much narrower in front than behind. Premaxillee 
and incisors projected much forwards, so as to be readily seen 
from above in front of the nasals ; the incisors themselves 
comparatively proodont, the incisive angle sometimes as much 
as 108°. Bullee small, an oblique horizontal measurement 
varying from 13°5 to 14 mm. 
Measurements of a skull (¢) from Colhué Huapi: 
occipito-nasal length 45 mm.; occipito-incisive length 46°6 ; 
nasals, length 15, breadth anteriorly 5, posteriorly 6°8 ; inter- 
orbital breadth 10°3 ; bullee, oblique horizontal length 14, 
Lange. Patagonia, from about 43°8. to 50°S. Specimens 
seen trom Chubut Colony, Lago San Martin, and various 
localities between, 
