1336 



CLASS MAMMALIA. 



existing species, which occur fossil in the caves of Brazil, the pre- 

 molars are normally - in number, but there is often but one of 



2 



these teeth in the lower jaw ; in A. {Palauchenid) magna from the 

 Pleistocene of Mexico, there were always two and occasionally three 

 lower premolars ; while in a Pleistocene South American species 

 (Hemiauchenia) there were three premolars in both jaws. In A. 

 (Holomeniscus) hesterna (fig. 1210, a), from the Pleistocene of North 

 America, on the other hand, the premolars were reduced to one in 



each jaw ; while A. (Eschatius) 

 vitakeriana has the same num- 

 ber, but is distinguished by the 

 simpler nature of the upper one. 

 The majority of the species were 

 of comparatively small size, but 

 A. magna and A. hesterna were 

 equal in bulk to the Camels of 

 the present day. 



Family Cervid^e. — The pres- 

 ent and three following families 

 of the suborder collectively 

 constitute the Pecora of re- 

 cent Zoology ; — a group well 

 denned at the present day, 

 but, as already mentioned, 

 connected in past epochs most 

 intimately by this family with 

 the Tragulida. The dentition 

 of the entire group is usually 



I. 



C. 



^\ Pm . 3, M. ?; 

 3 1 3 3 



upper incisors being invariably 

 absent. The true molars are 

 perfectly selenodont, and the 

 upper ones carry four columns ; 

 the second premolar is always 

 in contact with the third ; there 

 is a long interval, or diastema, 

 Fig. 121 1. —a, Dorsal aspect of the right manus between the lower premolars 



of Ox (Bos taunts) ; b, Do. of right pes of Red- , . , ■• ■, t . 



Deer (Cervus elaphus). Reduced, ca, Carpus ; and Canine ', and the latter IS 



ta, Tarsus ; c, Metapodium (cannon-bone). approximated tO, and closely 



resembles the incisors. The 

 third and fourth metapodials (fig. 1211) coalesce into a cannon- 

 bone ; the navicular and cuboid of the tarsus are likewise united ; 

 and the odontoid process of the axis vertebra forms a spout-like 



