The sea squirt has two openings in its small body. One opening, called the "oral siphon", sucks water into the animal; the other opening, called the "atrial siphon", squirts water out of the animal. Inside is a little basket-like sieve which traps food: so these sea squirts are filter feeders. The Sea squirt can close the holes in its siphons, like a drawstring can close the opening in a bag. 