CHAP. XVII.] 
MAMMALIA. 
217 
of the Palsearctic region, from the Sahara to Mongolia as far as 
Lake Baikal. Auchenia (4 species), comprehending the Llamas 
and Alpacas, is equally characteristic of the mountains and deserts 
of the southern part of South America. Two species entirely 
domesticated inhabit the Peruvian and Bolivian Andes; and two 
others are found in a wild state, the vicuna in the Andes of 
Peru and Chili (Plate XYI. vol. ii. p. 40), and the guanaco over 
the plains of Patagonia and Tierra del Fuego. 
Extinct Camelidce. — Mo fossil remains of camels have been 
found in Europe, but one occurs in the deposits of the SiwaJik 
Hills, usually classed as Upper Miocene, but which some natu- 
ralists think are more likely of Older Pliocene age. Meryco- 
therium, teeth of which have been found in the Siberian drift, is 
supposed to belong to this family. 
In North America, where no representative of the family now 
exists, the camel-tribe were once abundant. In the Post-pliocene 
deposits of California an Auchenia has been found, and in those 
of Kansas one of the extinct genus Procamelus. In the Pliocene 
period, this genus, which was closely allied to the living camels, 
abounded, six or seven species having been described from 
Nebraska and Texas, together with an allied form Homocamelus. 
In the Miocene period different genera appear, — Pcebrotherium, 
and Protomeryx , — while a Procamelus has been found in de- 
posits of this age in Virginia. 
In South America a species of Auchenia r has been found in 
the caves of Brazil, and others in the Pliocene deposits of the 
pampas, together with two extinct genera, Palceolama and Gamelo - 
therium. 
We thus find the ancestors of the Camelidae in a region where 
they do not now exist, but which is situated so that the now 
widely separated living forms could easily have been derived 
from it. This case offers a remarkable example. of the light 
thrown by palaeontology on the distribution of living animals ; 
and it is a warning against the too common practice of assuming 
the direct land connection of remote continents, in order to ex- 
plain similar instances of discontinuous distribution to that of 
the present family. 
