40 



A most interesting line, that leading to the Camels and Lla- 

 mas, separates from the primitive Selenodont branch in the 

 Eocene, probably through the genus Parameryx. In the Mio- 

 cene, we find in Poebrotherium and some nearly allied forms 

 unmistakable indications that the Cameloid type of ruminant 

 had already become partially specialized, although there is a 

 complete series of incisor teeth, and the metapodial bones are 

 distinct. In the Pliocene, the Camel tribe was, next to the 

 Horses, the most abundant of the larger mammals. The line is 

 continued through the genus Procamelus, and perhaps others, 

 and in this formation the incisors first begin to diminish, and 

 the metapodials to unite. In the Post-Tertiary we have a true 

 Auchenia, represented by several species, and others in South 

 America, where the Alpacas and Llamas still survive. From 

 the Eocene almost to the present time, North America has been 

 the home of vast numbers of the Camelidce, and there can be 

 little doubt that they originated here, and migrated to the Old 

 World. 



Returning once more to the upper Eocene, we find another 

 line of descent starting from Oromeryx, which, as we have 

 seen, had apparently then just become differentiated from the 

 older Bunodont type. Throughout the middle and upper 

 Miocene, this line is carried forward by the genus Leptomeryx 

 and its near allies, which resemble so strongly the Pliocene 

 Cervidce that they may fairly be regarded as their probable 

 progenitors. Possibly some of these forms may be related to 

 the Tragulidce, but at present the evidence is against it. 



The Deer family has representatives in the upper Miocene of 

 Europe, which contains fossils strongly resembling the fauna of 

 our lower Pliocene, a fact always to be borne in mind in com- 

 paring the horizon of any group in the two continents. Several 

 species of Cervidce, belonging to the genus Cosoryx, are known 

 from the lower Pliocene of the West, and all have very small 

 antlers, divided into a single pair of tynes. The statement 

 recently published, that most of these antlers had been broken 

 during the life of the animals, is unsupported by any evidence, 



