They have been around since Cambrian times, more than 500 million years ago. Sea squirts are invertebrate marine animals. Contrary to what the image might suggest, they have neither mouths nor eyes. They feed mainly on plankton and other organic matter which they filter through the water pumped through their bodies. The development of the ascidian is very surprising. When the fertilized eggs turn into larvae, they can swim freely. However, they cannot feed at this stage. To eat, they must find a