Starfish

Starfish or sea stars are a class of marine invertebrates generally shaped like a star polygon. (In common usage, these names are also often applied to ophiuroids, which are correctly referred to as brittle stars or basket stars.) Starfish are also known as asteroids because they form the taxonomic class Asteroidea (). About 1,900 species of starfish live on the seabed, and are found in all the world's oceans, from warm, tropical zones to frigid, polar regions. They can occur from the intertidal zone down to abyssal depths, at below the surface.

Hymenaster is a genus of sea stars (Asteroidea) of the family Pterasteridae.

species of echinoderm

The Forcipulatacea are a superorder of sea stars.

disease of starfish