On The Origin of Species by Charles Darwin Chapter 16 Page 4

A minute animal: generally applied to those visible only by the microscope.

ANNELIDS. — A class of worms in which the surface of the body exhibits a more or less distinct division into rings or segments, generally provided with appendages for locomotion and with gills. It includes the ordinary marine worms, the earth-worms, and the leeches.

ANTENNAE. — Jointed organs appended to the head in Insects, Crustacea and Centipedes, and not belonging to the mouth.

ANTHERS. — The summits of the stamens of flowers, in which the pollen or fertilising dust is produced.

APLACENTALIA, APLACENTATA or APLACENTAL MAMMALS. — See MAMMALIA.

ARCHETYPAL. — Of or belonging to