Emily Dickinson Lexicon

CRUST-A'CEOUS, a. [Fr. crustacée, from L. crusta.]

Pertaining to crust; like crust; of the nature of crust or shell. Crustaceous animals, or Crustacea, have a crust or shell composed of several jointed pieces, and in their external form have a great resemblance to insects; but in their internal structure and economy, they are quite different. They were arranged by Linnæus, in the same class with the insects, but now form a class by themselves. They include the crab, lobster, shrimp, &c. – Ed. Encyc.