Hierarchy classification:

1. top of the aat hierarchies
2. Agents Facet
3. Living Organisms (hierarchy name)
4. living organisms (entities)
5. Eukaryota (domain)
6. Animalia (kingdom)
7. Annelida (phylum)
8. Clitellata (class)

Anotations

Scope note:

Members of a subclass containing around 650 species of segmented worms characterized by a small sucker, which contains the mouth at the anterior end of the body and a large sucker located at the posterior end, having a flattened body, and being aquatic or living on moist soil. A few species have been used by humans in clinical bloodletting for thousands of years.