74 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
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 
ANA A 
a 
Fic. 3.—Four stages in the evolution of the cameline skull. A, Protylopus 
Upper Eocene; B, Poébrotherium, Lower Eocene; C, Procamelus, 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. 
