Procotylas' are only 0.25 to 0.8 cm long and whitish in colour. They are wider for their size than other planaris with large sucking mouths. Their heads are almost straight across or blunt. They suck in tiny animals or animal fluids to feed. On their heads they have 2 to 7 tiny eyes.
Planaria provide food for larger animals.
They help recycle materials from dead animals in the pond. They also help control small animals in the pond since they prey upon both dead and living small animals.