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various types of sheath in animals and plants:
(1) A cell wall in certain amoebae (thecamoebae).
(2) A chitinoid membrane in hydroid polyps; hence the division into the suborders Thecaphora and Athecata.
(3) The connective tissue surrounding ovarian follicles in vertebrates (theca folliculi).
(4) A tooth socket in the jawbone of mammals and crocodiles.
(5) A capsule for spores in mosses.
(6) The valve of a silicified test; in diatoms, the upper half is the epitheca and the lower half, the hypotheca.
(7) The pollen sac of an anther in angiosperms.