Operculum (fish) Operculum (fish) The operculum is a series of bones found in bony fish that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. The opercular series contains four bone segments known as the preoperculum, suboperculum, interoperculum and operculum. The preoperculum is a crescent-shaped structure that has a series of ridges directed posterodorsally to the organisms canal pores. The preoperculum can be located through an exposed condyle that is present immediately under its ventral margin; it also borders the operculum, suboperculum, and interoperculum posteriorly. The suboperculum is rectangular in
Sessility (motility) organisms, in which individuals of a particular species group closely to one another for beneficial purposes, and can be seen in coral reefs and cochineal populations. This allows for faster reproduction and better protection from predators. The circa littoral zone of coastal environments and biomes are dominated by sessile organisms such as oysters. Carbonate platforms grow due to the buildup of skeletal remains of sessile organisms, usually microorganisms, which induce carbonate precipitation through their metabolism. In anatomy and botany, "sessility" refers to an organism or biological structure that has no "peduncle" or stalk. See Peduncle (anatomy), Peduncle (botany) and Sessility