376 GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION. 



and Chili, aiid the guanaco the plains of Patagonia and Tierra del 

 Fuego. 



The Tertiary deposits of Europe have thus far yielded no traces 

 of the Camelidae, and if we except the Camelus Sivalensis and 

 C. antiquus, from the Siwalik Hills of India, and C. Thomasi, from 

 the Quaternary deposits of Algeria, the same may be said of the 

 Eastern Hemisphere generally. On the other hand, animals refer- 

 able in part to this family, and, again, others closely related to these, 

 are abundant in America, where they form a connecting series or 

 chain almost as complete as that which has been established for the 

 horse. The cameline line of descent has been traced by Professor 

 Cope from the Oligocene or Miocene Poebrotherium, in which, as 

 well as in the succeeding genus, the metapodial bones were dis- 

 tinct, and the mouth was furnished with a complete series of in- 

 cisor teeth, through Protolabis, Procamelus, and Pliauchenia (Plio- 

 cene), the last standing in the relation of its dentition intermedi- 

 ately between Procamelus and the camel. Auchenia, the llama, 

 which may be considered to terminate the series, is late Pliocene 

 and Post-Pliocene ; with it occur associated several related forms, 

 as Protauchenia, Palaeolama, &c. Professor Marsh indicates the 

 Eocene Parameryx as the probable most ancient ancestor of the 

 camels, whereas by Scott, Osborn, and Speir this place is given to a 

 contemporaneous genus Ithygrammodon. 



It would appear, therefore, that the camels are a New World 

 family, but this is by no means proved to be the case ; the absence 

 of the true camel in America and its occurrence in India in deposits 

 as ancient as the older Pliocene, render it very probable that an- 

 cestral cameline forms will be found in the Old World as well as 

 in the New. 



The chevrotains, or mouse-deer (Tragulidas), which comprise 

 some of the smallest of known ungulates,, and which in structure 

 stand in a measure intermediate between the deer and hog, are 

 ranged under two genera, Tragulus and Hysemoschus, the former 

 restricted to Southern and Southeast Asia, and the larger islands of 

 the Eastern Archipelago, and the latter to West Africa. The family 

 dates from the Miocene period, of which the genus Hysemoschus is 

 a belonging. 



Of the true ruminants, the Camelopardalidae, or giraffes, con- 

 stitute perhaps the most peculiar group. Only one species, Camelo- 



