Planaria are a type of non parasitic flatworm that is considered to be the simplest of all flatworms. Most of these worm are found in either fresh or salt water environments, but they can also be found on land in moist soils.Continue Reading
Planaria are often about a half inch long, are colored gray, brown or black, and have a flat, soft, wedge-shaped body. They have triangle-shaped head with two eye spots that are sensitive to light. They also have two ear-like projections at the base of their head that are sensitive to touch and a mouth of the underside of their bodies that are covered with hair-like cilia.
The Planaria have a simple brain and nervous system. They do not have circulatory or respiratory systems, however. Instead, they breath by diffusing oxygen and carbon dioxide through their body walls. Planaria eat larvae, small worms and crustaceans by extending a long tube from its mouth and dropping its digestive juices onto prey. They then consume the partially digested food.
Also Planaria contain both male and female organs. The sperm from one planarian is required to fertilize the eggs of another, however. They do have the ability to split into two pieces that then regenerate their missing parts and become two different planaria.Learn more about Zoology