Turritella \Tur`ri*tel"la\, n. [NL., dim fr. L. turris tower.]
(Zool.)
Any spiral marine gastropod belonging to {Turritella} and
allied genera. These mollusks have an elongated, turreted
shell, composed of many whorls. They have a rounded aperture,
and a horny multispiral operculum.
[1913 Webster]