36 ZOOLOGICAL GEOGEAPHY. [part hi. 



It is doubtful whether mammals or batrachians have any means 

 of passing, independently of man's assistance ; the former having 

 but one doubtfully indigenous representative, the latter none at 

 all. The remarkable absence of all gay or conspicuous flowers 

 in these tropical islands, though possessing a zone of fairly 

 luxuriant shrubby vegetation, and the dependence of this phe- 

 nomenon on the extreme scarcity of insects, has been already 

 noticed at Vol. I. p. 461, when treating of a somewhat similar 

 peculiarity of the New Zealand fauna and flora. 



/. Soiith Temperate America, or the Chilian Svh-region. 



This sub-region may be generally defined as the temperate 

 portion of South America. On the south, it commences with tlie 

 cold damp forests of Tierra del Fuego, and their continuation up 

 the west coast to Chiloe and northward to near Santiago. To the 

 east we have the barren plains of Patagonia, gradually changing 

 towards the north into the more fertile, but stUl treeless, pampas 

 of La Plata. Whether this sub-region should be continued across 

 the Eio de la Plata into Uruguay and Entre-rios, is somewhat 

 doubtful. To the west of the Parana it extends northward over 

 the Chaco desert, till we approach the border of the great forests 

 near St. Cruz de la Sierra. On the plateau of the Andes, how- 

 ever, it must be continued still further north, along the " paramos " 

 or alpine pastures, till we reach 5° of South latitude. Beyond this 

 the Andes are very narrow, having no double range with an inter- 

 vening plateau; and although some of the peculiar forms of the tem- 

 perate zone pass on to the equator or even beyond it, these are not 

 sufficiently numerous to warrant our extending the sub-region to 

 include them. Along with the high Andes it seems necessary to in- 

 clude the western strip of arid country, which is mostly peopled 

 by forms derived from Chili and the south temperate regions. 



Mammalia. — This sub-region is weU characterised by the pos- 

 session of an entire family of mammalia having Neotropical 

 affinities— the Chinchillidae. It consists of 3 genera — Chinchilla 

 (2 sp.), inhabiting the Andes of Chili and Peru as far as 9° south 

 latitude, and at from 8,000 to 12,000 feet altitude ; Lagidium 

 (3 sp.), ranging over the Andes of Chili, Peru, and South Ecuador, 



