This programed text, designed for upper elementary and middle school students, is intended to give students a basic knowledge of invertebrates. Students are expected to be able to identify, name, describe, classify to phylum, and draw animals studied in the text when the unit is completed. A pretest, a series of quizzes and are provided. The teacher's guide lists the behavioral objectives of the unit, and suggests methods of supplementing the text with illustrations and specimens. This work was prepared under an ESEA Title III contract. (AL)