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In botany, an operculum (pl.: opercula) or calyptra (from Ancient Greek καλύπτρα (kalúptra) 'veil') is a cap-like structure in some flowering plants, mosses, and fungi. It is a covering, hood or lid, describing a feature in plant morphology .
Normally, the insular opercula begin to develop between the 20th and the 22nd weeks of pregnancy. At weeks 14 to 16 of fetal development, the insula begins to invaginate from the surface of the immature cerebrum of the brain, until at full term, the opercula completely cover the insula. [4] This process is called opercularization. [5]
Operculum (animal), a structure resembling a lid or a small door that opens and closes Operculum (bird), a structure which covers the nares of some birds Operculum (bryozoa), a lid on the orifice of some bryozoans
Operculum or branchial operculum (plural opercula): One of the plates on the ventral surface of the abdomen, just in front of the epigastric furrow, covering the book lungs, often pale, yellow or orange in colour; two pairs in Mygalomorphae, one pair in other spiders [1] Opisthosoma: see abdomen
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
This goat has corneous horns. Gastropod shell of Viviparus contectus with its corneous operculum in place. Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals.
Arthrodontous capsule of the moss Dicranella varia Peristome of Bryum capillare. In mosses, the peristome is a specialized structure in the sporangium that allows for gradual spore discharge, instead of releasing them all at once.
Chimaeras lack spiracles, using gill opercula for buccal pumping instead. [8] Bony fish have similar gill opercula , but the basalmost ray-finned fish, bichirs , use their spiracles for inhaling air into their lungs; this leads to speculation this may be the original air breathing mechanism ancestral to all bony fish and tetrapods . [ 9 ]