horny, usually somewhat transluscent.

made of chitin, a semitransparent horny substance composing much of the hard 'skin' of crustaceans

semitransparent horny substance composing shell

Chitin: A resistant organic compound with the same basic carbohydrate structure as cellulose, but nitrogenous because some hydroxyl groups are replaced by ascetamide groups. It is a common constituent of various invertebrate skeletons such as insect exoskeletons and foraminiferal inner test, and also occurs in hyphae and spores of fungi.

Referring to chitin, a polysaccharide, often found in the outer shell of mollusks and insects. It forms a hard layer that contains and protects the inner components of the organism.

of or resembling chitin

Having the nature of chitin; consisting of, or containing, chitin.