Asterias

Asterias belong to the phylum Echinodermata and are starfish. Asterias can be found on rocks, kelp and mussel beds, sand, and mudflats. They feed on gastropods and bivalves by means of engulfment. They prey on bivalves by use or their tube-feet to adhere to the valves with a strong grip. Eventually the valves of the shell are pried far enough apart to allow Asterias to evert some of it's stomach folds out through the mouth and into the gap. A unique feature of Echinoderms is their water vascular system. Starfish exhibit a unique body symmetry known as Pentamerism. The Asterias skeleton is made up of many crystals of calcium carbonate. Asterias also has individual crystals which are modified into spines and have stalked pedicellariae scattered over their aboral surface. Asterias has the ability to reproduce both sexually and asexually. Asterias is commonly the prey of other starfish and mollusks.