coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

s, the coenosteum is the stony skeletal material secreted by the

coenosarc In corals, the coenosarc is the living tissue overlying the stony skeletal material of the coral. It secretes the coenosteum, the layer of skeletal material lying between the corallites (the stony cups in which the polyps sit). The coensarc is comp ...

, the layer of living material lying between the

corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can retract. The cup is composed of aragonite, a crystalline form of calcium carbonate, and is secreted by the polyp. Corallit ...

s (the stony cups in which the polyps sit). The coenosteum is composed of

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including prec ...

, a crystalline form of calcium carbonate, and is generally a spongy, porous material. Sometimes the coenosteum has ornamentation such as ridges and beads, visible as raised areas of the coenosarc. The coenosteum and corallites together are known as the corallum.

References

{{reflist Cnidarian anatomy