Planaria

Planaria sp., or cross-eyed worm, is a common freshwater flatworm. It moves by cilia on the ventral dermis, allowing it to glide along on a film of mucus.Planaria have 2 eyespots that act as photoreceptors. Being light sensitive they shy away from light. Some move by undulations of the whole body by the contractions of muscles built into the body wall. Planaria are a member of the class Turbellaria and the phylum of flatworms, Platyhelminthes. They exibit an extraordinary ability to regenerate lost body parts. It size range from 3 to 12mm and your body has two eye-spots (also known ocilli), used to move away from light sources. For example a Planria split length wise or crosswise will regenerate into 2 separate individuals. Planaria can are common to many parts of the workd and reside in fresh water ponds.

The more frequently used in laboratory is the brownish Dugesia tigrina. Other common varieties is the blackish Planaria maculata and Planaria dorotocephalia.