chitinous
From ZooTerms (Dictionary of Invertebrate Zoology)
chitinous (adjective; Greek chiton, tunic): (Arthropoda) Composed of or resembling chitin, a colorless, hard amorphous compound; seen as the principal constituent of the hard covering of insects and crustaceans, the horny material as in the ligament of bivalve mollusks, the internal shell remnant of the squids and the horny operculum of many gastropods.
