echinoid
9.7
An animal that lives in the sea with a spiny shell, like a sea urchin
- noun
- /ˈɛkɪnɔɪd/
- Specialized
:
equinoide
- An echinoid, such as the sand dollar, has a distinctive flat shape and a hard, spiny surface.
Examples
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Many marine biologists study echinoids to understand their role in the ecosystem.
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PHOTO (BLACK & WHITE): Figure 24. Echinoid echinoderms, examples of sea urchins, Figure 5, p. 6, from Serafy and Fell (1985).
Academic text (1996) -
The echinoid is often found on rocky shorelines, where it burrows into the sand.
Surface Forms
Morphology
echinoid = echinoderm (semi-transparent) = echino + oid
The noun is formed from the combining form 'echino-' plus '-oid'; this signals a relation to sea urchins but relies on technical taxonomic vocabulary rather than common roots.
Etymology
Echinoid as a noun uses the Greek echinos 'hedgehog' plus the ending -oid 'like', so it names a spiny sea creature such as a sea urchin or sand dollar. That's why an echinoid is a marine animal with a round, spiny shell.
