Wikipedia
The proboscisless leeches, Arhynchobdellida, are classified as an order of the Hirudinea. But leech taxonomy and systematics will eventually be revised in due time, not because there are many uncertainties about their phylogeny, but because the major clades of clitellate annelids - and whether the clitellates are themselves a clade - have not been fully elucidated. For example, the "true leeches" ( Euhirudinea) might actually be synonymous with the Hirudinea, as all other leech-like annelids might not be very closely related to the true leeches.
Proboscisless leeches are generally freshwater or amphibious animals. They have usually 6-8, sometimes 5 pairs of eyes. Some - among them the well-known European Medical Leech (Hirudo medicinalis) of the Hirudiniformes - are bloodsuckers, while most - including the Kinabalu Giant Red Leech (Mimobdella buettikoferi) of the Erpobdelliformes - are predators that hunt small invertebrates which are swallowed whole.