a class of Annelida, the members of which are ectoparasitic on a great variety of aquatic and terrestrial animals; they possess anterior and posterior suckers, and most of them lack setae; hermaphrodi, pikliku lameda (harva silindrilise) kehaga, jäsenditeta ja, v.a. harjaskaanid (Acanthobdella), harjasteta rõngusside klass ... K-de pikkus on 1-20 cm, keha koosneb peasagarast ja 33 segmendist; igale