EVERYDAY SCIENCE

Detailed explanation-1: -Leeches are currently included in the Class Clitellata, Superorder Euhirudinea (Table 1).

Detailed explanation-2: -Leeches are segmented worms in the Subclass Hirudinea that are usually ectoparasitic. They belong to the Class Clitellata (along with earthworms, Subclass Oligochaeta) because of the presence of a clitellum, which is a swelling towards the head of the animal, where the gonads are located.

Detailed explanation-3: -The class Hirudinea comprises two orders: Arhynchobdellida and Rhynchobdellida: The arhynchobdellids are divided into three families: Haemopidae, Hirudinidae, and Erpobdellidae. The haemopids and hirudinids have relatively large mouths, occupying the entire cavity of the oral sucker.

Detailed explanation-4: -Phylum Annelida contains the class Polychaeta (the polychaetes) and the class Oligochaeta (the earthworms, leeches, and their relatives).

Detailed explanation-5: -Annelida: Body of a leech is elongated with ringlike segments. They have suckers for locomotion and feeding purposes. Leeches belong to the phylum annelida.