There are many types of sea stars. Some like the biscuit star are modeled on five arms, except with this sea star the arms are filled in. Sea stars are missing many features that other animals have. It’s very hard to work out if it really has a head. There is a top and a bottom, but no front and back. They seem to have missed out on eyes, so maybe they don’t need for a head. The mouth is on the underside where the five legs meet in the middle.
The mouth looks like a beak with many jaws. Its table manners are very different. They find their victim, crawl over it and then force their stomach out of their mouth. The stomach juices start the digestion process and everything is sucked back in again.
Their coolest feature is their hydraulic water pumping system. Sea stars, sea urchins and sea cumbers use a water pumping system to help them move. The water they pump helps to move their arms and the thousands of small tentacles lining the arms. These small tentacles are called tube feet.
Biscuit stars come in many interesting colour patterns, but they mostly belong to the one species.