CHAP. XVII.] 
MAMMALIA. 
237 
Family 63.— CHINCHILLIE.E. (3 Genera, 6 Species ) 
General Distribution. 
Neotropical 
Sub-regions. 
Nearctic 
Sub-regions, 
P ALAS ARCTIC 
Sub-regions. 
Ethiopian 
Sub-regions. 
Oriental 
Sub-regions. 
Australian 
Sub-regions. 
1 
The Chinchillidae, including the chinchillas and viscachas, are 
confined to the alpine zones of the Andes, from the boundary of 
Ecuador and Peru to the southern parts of Chili ; and over the 
Pampas, to the Rio Negro on the south, and the River Uruguay 
on the east. Chinchilla (2 sp.), the true chinchillas, are found 
in the Andes of Chili and Peru, south of 9° S. lat., and from 
8,000 to 12,000 feet elevation (Plate XYI. vol. ii. p. 40) ; Lagi - 
dium (3 sp.), the alpine viscachas, inhabit the loftiest plateaus 
and mountains from 11,000 to 16,000 feet, and extend furthest 
north of any of the family ; while Lagostomus (1 sp.), the vis- 
cacha of the Pampas, has the range above indicated. The family 
is thus confined within the limits of a single sub-region. 
Extinct Chinchillidce. — Lagostomus has been found fossil in 
the caves of Brazil, and in the Pliocene deposits of La 
Plata. The only known extinct forms of this family are Ambly - 
rhiza and Loxomylus, found in cavern-deposits in the island of 
Anguilla, of Post-Pliocene age. These are very interesting, as 
showing the greater range of this family so recently ; though its 
absence from North America and Europe indicates that it is a 
peculiar development of the Neotropical region. 
Family 64. — OCTOBONTIDiE. (8 Genera, 19 Species.) 
General Distribution. 
Neotropical 
Nearctic 
Palaearctio 
Ethiopian 
Oriental 
Australian 
Sub-regions. 
Sub-regions. 
Sub-regions. 
Sub-regions. 
Sub- regions. 
SUB-REGI OIT3. 
