The Hirudinea Class is split into smaller groups, called Orders. Below is a list of some Hirudinea Orders:
Gnathobdellida Order: Includes Freshwater Leeches.
All of the Orders above have been split into smaller groups, called Families. Families are then split into Genera. Remember, as each group gets smaller, organisms in that group are more and more alike. Each Genus will contain individual Species.
Information on specific Families and Genera is not included on this website, but you can find out which groups a species belongs to by checking the Classification Box at the bottom of each Species Page. See the example of an Freshwater Leech below:
Freshwater Leech: