(subclass Zoantharia, order Madreporaria)
A suborder of colonial corals composed of small corallites, which first appeared in the Middle Triassic. They are characterized by having septa formed from relatively few (not more than eight) trabeculae and usually they have no more than two cycles of tentacles arranged in a single ring around the mouth, which leads to a smooth stomodaeum. The suborder contains five families, with 46 genera.
Subjects: Zoology and Animal Sciences.