What is "epitheca"

Epitheca \Ep`i*the"ca\, n. [NL., fr. Gr. 'epi` upon + ? a case, box, fr. ? to place.] (Zo["o]l.) A continuous and, usually, structureless layer which covers more or less of the exterior of many corals.

n. (context microbiology planktology English) The upper half of the theca of a thecate protist such as a diatom or dinoflagellate.

Epitheca is a genus of dragonflies in the family Corduliidae. They are commonly known as baskettails.

Some authorities spin off the North American baskettails into two new genera, Epicordulia and Tetragoneuria, but this has not gained widespread acceptance and most references place them under this genus.