CHAP. XVII. j 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 XVL vol. ii. p. 40), and the guanaco over 

 the plains of Patagonia and Tierra del Fuego. 



Extinct Camelidce. — No fossil remains of camels have been 

 found in Europe, but one occurs in the deposits of the Siwalik 

 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 Honiocamelus. 

 In the Miocene period different genera appear, — Pcehrotherium, 

 and Protomeryx, — while a Procamelus has been found in de- 

 posits of this age in Virginia. 



In South America a species of Auchenia has been found in 

 the caves of Brazil, and others in the Pliocene deposits of the 

 pampas, together with two extinct genera, Palmolama and Camelo- 

 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. 



