Hello,

There are many different species of flatworms. Some of the more common species, such as Procotyla fluviatilis, can grow up to almost an inch in length and are often brown or greenish in colour. Flatworms do have brains, which are not only able to learn but regenerate and remember previous actions.

Characteristics: Flatworms are unsegmented worms with a tail and the head end. They are bilaterally symmetrical with a definite and upper and lower surface. They have no body cavity or no specialized respiratory or circulatory organs. This is the reason behind the flat shape , common to all flatworms. they depend on a large surface to allow oxygen and nutrition to diffuse into their bodies. Most species are hermaphrodite, having both female and male reproductive organs.