74 READINGS IN EVOLUTION, GENETICS. AND EUGENICS 



suppressed; the upper end fuses wilh ihe tibia, while the lower remains 

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

 bone. Thefeetare very long and slender, with two toes in each; the 



B A 



Fig. 3. — Four stages in the evolution of the camehne skull. A, Protylopiis, 



Upper Eocene; B, Poebrothcrium, Lower Oligocene; C, Procawe/^J, 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. 



f 



