 More than 140 endemic flatworm (Plathelminthes) species are in Lake Baikal, where they occur on a wide range of bottom types.Most of the flatworms are predatory, and some are relatively brightly marked.They are often abundant in shallow waters, where they are typically less than long, but in deeper parts of the lake, the largest, "Baikaloplana valida", can reach up to when outstretched.