Theca
Theca , noun
[Latin, from Greek {not transcribed} a case to put anything in. See 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.
(a) (Zoology) The chitinous cup which protects the hydranths of certain hydroids.
(b)
(Zoology) The more or less cuplike calicle of a coral.
(c)
(Zoology) The wall forming a calicle of a coral.