Theca

From Palaeos

A tough shell or covering enclosing the body or part of the body of an organism. Structures covered by the term "theca" may be secreted by the animal directly and be rigid (e. g. the shell of a mollusc) or leathery, or may be constructed using material collected from the surrounding environment (many protozoans such as Xenophyophorea).

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CKT070301