Facts about corals

-Corals belong to the Phylum Cnidaria. Cnidaria means that they are invertebrates which means they do not have bones and all have specialized cells called nematocysts that help them capture prey and defend themselves and it exhibit radial symmetry
the passing water.
-Corals belong to the Class Anthozoa - a subgroup of the Phylum Cnidaria. Members of this group of animals have flower-like structures called polyps. They have a simple body plan in which food and air passes in and out of a stomach-like sac called gastrovascular cavity through a single opening which are usually belonging on to two major phyla, the Cnidaria and the Platyhelminthes.
-Corals typically form colonies consisting of many individual corals.
-Coral colonies grow from a single founder individual that divides repeatedly. A coral colony consists of a base that attaches coral to a reef, an upper surface that is exposed to light and hundreds of polyps.

source:http://animals.about.com/od/cnidarians/a/tenthingscoral.htm