Webster's 1828 Dictionary
CRUSTACEOUS
a.[L.] 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 Linne, in the same class with the insects, but now form a class by themselves. They include the crab, lobster, shrimp, etc.
CRUSTACEOUSNESS
n.The quality of having a soft and jointed shell.
Webster's 1913 Dictionary
CRUSTACEOUS
Crus *ta "ceous (krs-t "shs; 97 ), a. Etym: [NL. crustaceous. See crustacea. ]
1. Pertaining to, or of the nature of, crust or shell; having a crustlike shell.
2. (Zoöl.)
Defn: Belonging to the Crustacea; crustacean.
CRUSTACEOUSNESS
CRUSTACEOUSNESS Crus *ta "ceous *ness, n.
Defn: The state or quality of being crustaceous or having a crustlike shell.
The Wordsmith Dictionary