chapter XIV

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[6] Each of these higher groups has a proper name composed of a single word. In the case of no group except the species is a name-word ever duplicated. Each genus, family, order, or higher group has a name-word peculiar to it, and belonging to it alone.

## CHAPTER XV BRANCH PROTOZOA: THE ONE-CELLED ANIMALS

Of this group the structure and life-history of the Amœba (_Amœba_ sp.) and the Slipper Animalcule (_Paramœcium_ sp.) have already been treated in