EVIDENCES EROM PALAEONTOLOGY 



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suppressed; the upper end fuses with the tibia, while the lower remains 

 as a small separate bone, wedged in between the tibia and the heel- 

 bone. The feet are very long and slender, with two toes in each; the 



Fig. 32. — Four stages in the evolution of the cameline skull. A, Protylopus, 

 Upper Eocene; B, Po'ebr other ium, Lower Oligocene; C, Procamchis, Upper Miocene; 

 D, guanaco, Recent. (From Scott.) 



long bones of the foot are co-ossified to form a "cannon-bone," the 

 very young skeleton showing that this co-ossification does actually take 

 place. The toes proper are free, giving the "cloven hoof," but the 

 hoofs are very small and the weight is carried upon a soft, thick pad. 



