Columbella mercatoria

from The Collaborative International Dictionary of English v.0.48

Columbella \Col`um*bel"la\, n. [NL., dim. of L. columba a dove.
   So called from a fancied resemblance in color and form, of
   some species.] (Zool.)
   A genus of univalve shells, abundant in tropical seas. Some
   species, as {Columbella mercatoria}, were formerly used as
   shell money.
   [1913 Webster]