HISTORY OF THE ARTIODACTYLA 391 



found abundantly in the Pleistocene of Ecuador, Brazil and 

 Argentina. Another possibility is that both phyla did actually 

 migrate to both continents and that only the camels succeeded 

 in permanently establishing themselves in Asia and only the 

 llamas in South America, though for this solution the fossils 

 afford no evidence. 



The camels of the upper Miocene did not differ sufficiently 

 from those of the lower Pliocene to call for special notice other 

 than to remark that the two phyla of the true camels and the 

 llamas were hardly distinguishable and one genus (fPro- 

 camelus) may have been ancestral to both. In the middle 

 Miocene the browsing camels {] Alticamelus) reached the 

 acme of their importance and made no great progress subse- 

 quently. The generalized stock, from which the upper Mio- 

 cene and lower Pliocene \Procamelus descended, was repre- 

 sented by ]Protolabis and \Miolabis, smaller animals, which 

 had a full set of upper incisors and premolars and the grinding 

 teeth were not so high-crowned. In most of the species the 

 metapodials had not fused to form cannon-bones and probably 

 there were no pads on the feet, though ^Alticamelus, the 

 t Giraffe-Cam el, had already developed both cannon-bones 

 and pads. 



In the lower Miocene the fgiraffe-camels were represented 

 by the genus ^Oxydactylus, which was a considerably smaller 

 animal than its successor ]Altica7nelus, of the middle Miocene 

 and later formations, and had shorter neck and legs. The 

 teeth, though brachyodont, were not very low-crowned. There 

 was no cannon-bone, the two metapodials of each foot remain- 

 ing separate. An especially noteworthy feature in this genus 

 is to be observed in the character of the hoofs, which, as the 

 ungual phalanges demonstrate, were narrow and pointed, 

 like those of antelope and deer, and carried most of the weight. 

 The member of the grazing series {\Protomeryx) was smaller 

 in every way than its contemporary {]Oxydactylus) of the 

 browsing Une and had shorter neck and legs, though these were 



