protozoon

In Europe a peculiar ciliated Protozoon (Trichodina spongill) is found attached to the external surface of freshwater sponges.

For we may look at this matter in another light, and say our exuberant protozoon has shed a daughter, and remains.

I dissent quite from what you say of the myriads of years it would take to people the world with such imagined protozoon.

This protozoon secretes a shell about itself which has a characteristic shape, and often carries spines.

Now, if so, how long would it take to obtain an elephant from a protozoon or even from a tadpole-like fish?