356 UNGULATA. 



prsemolar, -which is separated by a wide gap from the rest of 

 the molar series, and is pointed in form. In the lower jaw 

 there is also a canine, placed a little behind the incisors, and 

 a detached laniariform premolar (the latter sometimes absent). 

 In the Llamas these isolated premolars are wanting. In the 

 living Camelidce the upper incisors, as we have seen, are re- 

 duced to two in number, but in some of the extinct types 

 of the family (e.g., the Pliocene Protolahis) we find that the 

 series of incisors is complete, being six in number in eacli 

 jaw. 



The foot in the Camelidce terminates in two toes, furnished 

 with imperfect nail-like hoofs, and the second and fifth toes 

 are wanting. In the Miocene Poebrothcrium the metacarpals 

 and metatarsals remain distinct from one another throughout 

 life (as in the living Hyomoschus). Horns are not known to 

 have been developed in any of the Camelida:. The Camelidce 

 make their first apjDearance, so far as known, in the Lower 

 Miocene of Xorth America, where the family is represented 

 by the genera Foehrothcrium and Protomeryg:, tlie former of 

 these having the embryonic character, that the metapodials do 

 not coalesce to form a " canon-bone." In the Old World, on 

 the other hand, the first recorded appearance of the Camelida: 

 is in the Siwalik deposits of India, which are generally re- 

 garded as of Upper Miocene age. Here we meet with the 

 existing genus Camelus. In the Pliocene deposits of North 

 America we have a number of extinct types of the Camelidce. 

 Of these Procamelus (fig. 648, B and c) seems to have re- 

 sembled the true Camels in most respects, and one species was 

 about as large as the existing Camels ; but there were four 

 praemolars on each side of each jaw, instead of three only. 

 Though characteristically Pliocene, this genus has also been 

 found in the Miocene of North America. Homocamelns re- 

 sembles the preceding in some respects, but has large canines 

 and isolated first upper premolars ; while Merycodus shows 

 some peculiarities in the structure of the molar teeth. In 

 the Pliocene of South America we meet with the two extinct 

 generic types Pcdceolamu and Camelotherium. ; and the living 

 genus Auchenia, comprising the Llamas and Alpacas, seems 

 to have come into existence at the same time. Eemains of 



