Test

n. pl. E. Tests (#), L. Testæ (#).

1. (Zoöl.) The external hard or firm covering of many invertebrate animals.
2. (Bot.) The outer integument of a seed; the episperm, or spermoderm.

The test of crustaceans and insects is composed largely of chitin; in mollusks it is composed chiefly of calcium carbonate, and is called the shell.