theca

The"ca, n.; pl. Thecæ. Etym: [L., fr. Gr. Tick a cover.] 1. A sheath; a case; as, the theca, or cell, of an anther; the theca, or spore case, of a fungus; the theca of the spinal cord. 2. (Zoöl.) (a) The chitinous cup which protects the hydranths of certain hydroids. (b) The more or less cuplike calicle of a coral. (c) The wall forming a calicle of a coral.

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