Amphioxus is a microphagus animal feeding on diatoms, desmids, protozoans and other pelagic microscopic organisms, suspended in sea water. Amphioxus is a ciliary or filter feeder. It is a marine animal commonly found in shallow water preferably brackish water, on the sandy coasts. The animal leads a sedentary life buried in sand, with only the anterior body end protruding out into water. Food particles are filtered from the current of water entering pharynx through mouth and finally going out through atriopore.