Rugosa
Videos
The Rugosa are an extinct class of solitary or colonial corals that were abundant in Middle Ordovician to Late Permian seas.
A close view of a Petoskey stone. Actually the colonial rugose coral Hexagonaria, a columnariine from Middle Devonian Michigan.
Three views of Grewingkia canadensis, a solitary streptelasmatine from Ordovician Indiana
Cyathophylloides sp., a colonial stauriine from the Late Ordovician, Georgian Bay Formation, Ontario, Canada
Scleractinia
Videos
Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrica
Diagram showing a coral polyp, its corallite, coenosarc and coenosteum
Diploria labyrinthiformis, a brain coral
Meandering corallite walls of an intratentacular budding coral