HOLOTHURIOIDEA
Hol`o*thu`ri*oi"de*a, n. pl. Etym: [NL. See Holothure, and -oid.]
(Zoöl.)
Definition: One of the classes of echinoderms.
Note: They have a more or less elongated body, often flattened
beneath, and a circle of tentacles, which are usually much branched,
surrounding the mouth; the skin is more or less flexible, and usually
contains calcareous plates of various characteristic forms, sometimes
becoming large and scalelike. Most of the species have five bands
(ambulacra) of sucker-bearing feet along the sides; in others these
are lacking. In one group (Pneumonophora) two branching internal
gills are developed; in another (Apneumona) these are wanting. Called
also Holothurida, Holothuridea, and Holothuroidea.
Source: Webster’s Unabridged Dictionary 1913 Edition