Ex`o*skel"e*ton (?), n. [Exo- +
skeleton] (Anat.) The hardened parts of the
external integument of an animal, including hair, feathers, nails,
horns, scales, etc.,as well as the armor of armadillos and many
reptiles, and the shells or hardened integument of numerous
invertebrates; external skeleton; dermoskeleton.