65:2.4
The higher protozoan type of animal life soon appeared, and appeared suddenly. And from these far-distant times the ameba, the typical single-celled animal organism, has come on down but little modified. He disports himself today much as he did when he was the last and greatest achievement in life evolution. This minute creature and his protozoan cousins are to the animal creation what bacteria are to the plant kingdom; they represent the survival of the first early evolutionary steps in life differentiation together with failure of subsequent development.