40 
REVISTA CHILENA DE HISTORIA NATURAL 
Skull apparently somewhat smaller than in A. fuscus, 
but the age of the type is not very certainly determinable. 
Anterior part narrower, the 'breadth between the outer 
corners of the anteorbital foramina and the interorbital 
breadth both distinctly less. 
Incisors very stout and heavy, decidedly thicker 
than in specimens of A. fuscus of apparently similar age. 
Dimensions of the type: — 
Tail (vertebrse in skin) 64; hind foot (dry) 28. 
Skull: tip of nasals to back of frontals 28 5; greatest 
breadth 23; nasals 15X6 3; interorbital breadth 7 5; 
breadth between outer corners of anteorbital foramina 
17'6; palatilar length 16 2; front of incisors to back of 
215; upper tooth-row (crowns) 8.4; combined breadth 
of upper incisors 4 7. 
Hah. Osorno^ S. Chili. 
Type. Adult. B. M. no. 16. 11. 14.4. Presented by 
Mr. Carlos E. Porter to Mr. J. A. Wolffsohn. 
The British Museum contains eleven specimens of 
Aconcemys fuscus, received at different dates from Mr. 
T. Bridges, but whether all were from the "Valle de Las 
Cuevas, on the east side of the Andes, near the Volcano 
of Peteroa, altitude 6000"', where Mr. Bridges discovered 
the species^ there is, unfortunately, no evidence to show. 
But all agree in the characters used above in separating 
the southern form, which is probably an inhabitant of the 
high slopes on the Volcano of Osorno, some little distance 
from the town of the same name. 
Since the time of Mr. Bridges no examples of this 
genus have come to the British Museum, nor has our 
indefatigable correspondent Mr. Wolffsohn been able to 
see or hear of any. Consequently this additional specimen, 
representing a second and more southern species of the 
genus, is an extremely welcome accession. 
