plural of ark shell

(malacology) Any of the family Arcidae of saltwater clams or marine bivalve molluscs.

plural of boat shell

(zoology) A marine gastropod of the genus Crepidula. The species are numerous. / (zoology) A marine univalve shell of the genus Cymbium, syn. Cymba.

plural of sheep-split

(dated) A split of a sheepskin; one of the thin sections made by splitting a sheepskin with a cutting knife or machine.

silly; simple-minded; stupid

Any bivalve shell of the genus Mactra.

plural of trough-shell

Dated form of shellac.