2. (Zo["o]l.)
(a) A soft tactile appendage of the mantle of many
Mollusca, and of the parapodia of Annelida. Those near
the head of annelids are Tentacular cirri; those of
the last segment are caudal cirri.
(b) The jointed, leglike organs of Cirripedia. See
{Annelida}, and {Polych[ae]ta}.
Note: In some of the inferior animals the cirri aid in
locomotion; in others they are used in feeding; in the
Annelida they are mostly organs of touch. Some cirri
are branchial in function.
3. (Zo["o]l.) The external male organ of trematodes and some
other worms, and of certain Mollusca.
4. (Meteor.) See under {Cloud}.