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Webster 1913 Edition
Echinodermata
‖
E-chiˊno-der′ma-ta
(ē̍-kīˊnō̍-dẽr′mȧ-tȧ)
, Noun.
pl.
[NL., fr. Gr.
ἐχῖνοσ
hedgehog, sea urchin + δέρμα
, -ατος
, skin.] (Zoöl.)
One of the grand divisions of the animal kingdom. By many writers it was formerly included in the Radiata.
[Written also
Echinoderma
.] ☞ The species usually have an exterior calcareous skeleton, or shell, made of many pieces, and often covered with spines, to which the name. They may be star-shaped, cylindrical, disk-shaped, or more or less spherical. The body consists of several similar parts (spheromeres) repeated symmetrically around a central axis, at one end of which the mouth is situated. They generally have suckers for locomotion. The group includes the following classes: Crinoidea, Asterioidea, Ophiuroidea, Echinoidea, and Holothurioidea. See these words in the Vocabulary, and also
Ambulacrum
.