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
Caudal Deportivo Mieres" after the Spanish Civil War, as all foreign denominations were forbidden. In 1946 Caudal first reached the third division, promoting to the second five years later – the "Segunda División B" category would only see the light of day in the late-1970s. Starting in 1980 and with the exception of one year, the club would spend the following 18 seasons in the fourth level, then play seven out of eight years in the third, being relegated back in 2004. Caudal won its group in the 2009–10 season – it had already finished first in 2006–07, albeit without promotion –