CHAP. XIV.] 
THE NEOTEOPICAL EEQION. 
37 
from 11,000 to 16,000 feet altitude; and Lagostomus (1 sp.), the 
" viscacha,” confined to the pampas between the Uruguay and 
Bio Negro. Many important genera are also confined to this sub- 
region. Auchenia (4 sp.), including the domesticated llamas 
and alpacas, the vicugna which inhabits the Andes of Peru and 
Chili, and the guanaco which ranges over the plains of Patagonia 
and Tierra del Fuego. Although this genus is allied to the Old 
World camels, it is a very distinct form, and its introduction from 
North America, where the family appear to have originated, may 
date hack to a remote epoch. Ursus ornatus, the “ spectacled 
bear ” of the Chilian Andes, is a remarkable form, supposed to be 
most allied to the Malay bear, and probably forming a distinct 
genus, which has been named Tremardos. Four genera of Octo- 
dontida?. are also peculiar to this sub-region, or almost so; Habro- 
comus (1 sp.) is Chilian ; Bpalacopus (2 sp.) is found in Chili and 
on the east side of the southern Andes ; Ododon (3 sp.) ranges 
from Chili into Peru and Bolivia ; Ctenomys (6 sp.) from the 
Straits of Magellan to Bolivia, with one species in South Brazil, 
Dolichotis , one of the Cavies, ranges from Patagonia to Mendoza, 
and on the east coast to 37§° S. latitude. Myopotamus (1 sp.), 
the coypu (Echimyidse), ranges from 33° to 48° S. latitude on 
the west side of the Andes, and from the frontiers of Peru to 
42° S. on the east side. Beithrodon and Acodon, genera of 
Murid se, are also confined to Temperate South America; Toly- 
peutes and Chlamydoph orus, two genera of armadillos, the latter 
very peculiar in its organization and sometimes placed in a dis- 
tinct family, are found only in La Plata and the highlands of 
Bolivia, and so belong to this sub- region. Otaria, one of the 
a eared seals ” (Otariidse), is confined to the coasts of this sub- 
region and the antarctic islands. Deer of American groups ex- 
tend as far as Chiloe on the west, and the Straits of Magellan on 
the east coast. Mice of the South American genera Hesperomys and 
Beithrodon , are abundant down to the Straits of Magellan and 
into Tierra del Fuego, Mr. Darwin having collected more than 20 
distinct species. The following are the genera of Mammalia 
which have been observed on the shores of the Straits of Magel- 
lan, those marked * extending into Tierra del Fuego : 
