Coral
Coral and sea anemones contain the simplest form of a nervous system. There is no central of the nervous system; therefore they don't have a brain. Neurons communicate with one another whenever they cross the path of another. The neurons send the information in almost every direction and lay between the two layers of each the coral.
Corals generally live in colones and are given credit to be the greatest reef builders. Corals grow but leaking out a calcium buildup in their pores, slowly adding onto themselves as time goes on. A coral "head" is a colony of myriad genetically identical polyps. Each polyp is a spineless animal typically only a few millimeters in diameter and a few centimeters in length. A set of tentacles surround a central mouth opening. An exoskeleton is excreted near the base. Over many generations, the colony thus creates a large skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.
Corals generally live in colones and are given credit to be the greatest reef builders. Corals grow but leaking out a calcium buildup in their pores, slowly adding onto themselves as time goes on. A coral "head" is a colony of myriad genetically identical polyps. Each polyp is a spineless animal typically only a few millimeters in diameter and a few centimeters in length. A set of tentacles surround a central mouth opening. An exoskeleton is excreted near the base. Over many generations, the colony thus creates a large skeleton that is characteristic of the species. Individual heads grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon.