Flatworm
This Flatworm, also known as the Polycladida, is commonly found in underwater volcanic zones and coral reefs.It is basically marine flatworm. It is soft-bodied, unsegmented, has no skeleton no body cavity. Even though this organism doesn't have a respiratory, or circulatory system, it does have a digestive. It has a combined digestive/excretory system – taking food in and getting rid of wastes through the same opening. Because of this its digestive system bares many similarities to that of the tapeworm.Being flat means most can’t swallow their prey. Instead, the pharynx (a part of the gut) is pushed out through the mouth. The pharynx engulfs the prey outside the worm’s body. Or digestive juices are injected into the prey and the resulting liquefied meal is then sucked up. Most flatworms don’t have an anus and they spit out indigestible bits through the mouth. Flatworms are carnivorous predators and scavengers. They feed mainly on bacteria, protozoans, other small invertebrates, and other available animal matter.