• A marine gastropod of the genus Crepidula. The species are numerous. It is so named from its form and interior deck. • A marine univalve shell of the genus Cymba.
Boat' shell` (Zoology) (a) A marine gastropod of the genus Crepidula . The species are numerous. It is so named from its form and interior deck. (b) A marine univalve shell of the genus Cymba .