Explain the ophiothrix of echinodermata which belongs to non chordate phyla?

The ophiothrix is also known as brittle star. It occurs in the shallow part of sea. They kill the animals with the help of their arms. Their target animals are mollusca and crustaceans. Their swimming action resembles that of snake. They do take debris and mud. They have a disc which arise and give rise to many arms. The spines are also present on the arms which help to grip the object. They have no anus and have poorly developed tube feet. The oral surface has mouth and a madreporite.