Chitin is a hard, semitransparent material found throughout the natural world.
The exoskeletons of members of the Lirin species are composed of Chitin and they sometimes refer to the structure simply as the Chitin, During the Kaylar coup on Rigel VII in 2254 Nano's chitin protected him, but was damaged by the impact of a Kaylar mace. (EV comic: "Our Dearest Blood")
The shells of Benzites are also chinitous. (DS9 novel: Devil in the Sky)
Megapedes on Quilian IV had a segmented chitinous exterior. (FASA RPG module: Safari in Violet)