GENERAL DISTRIBUTION. __________________________________/\__________________________________ / \ NEOTROPICAL| NEARCTIC |PALÆARCTIC | ETHIOPIAN | ORIENTAL | AUSTRALIAN SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS. -----------+-----------+-----------+-----------+-----------+------------ | | | | | 1 -- -- -- |-- -- -- --|-- -- -- --|-- -- -- --|-- -- -- --|-- -- -- -- | | | | | The Chinchillidæ, 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 XVI. vol. ii. p. 40); _Lagidium_ (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 viscacha of the Pampas, has the range above indicated. The family is thus confined within the limits of a single sub-region. _Extinct Chinchillidæ._--_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 _Amblyrhiza_ 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.--OCTODONTIDÆ. (8 Genera, 19 Species.) GENERAL DISTRIBUTION. __________________________________/\__________________________________ / \ NEOTROPICAL| NEARCTIC |PALÆARCTIC | ETHIOPIAN | ORIENTAL | AUSTRALIAN SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS. -----------+-----------+-----------+-----------+-----------+------------ | | | | | 1. 2 -- 4 |-- -- -- --|-- 2 -- -- |1 -- -- -- |-- -- -- --|-- -- -- -- | | | | |