Practice question

Leeches represent highly specialized derived annelids classified under Class Hirudinea distinguished by dorsoventrally flattened body, fixed number 32 internal segments externally subdivided by annulations, complete loss setae and septa except anterior, presence anterior sucker surrounding mouth and large posterior sucker for attachment and inchworm locomotion, clitellum only during breeding secreting cocoon, hermaphroditic with direct development, predominantly freshwater but also marine terrestrial, many sanguivorous ectoparasites feeding on vertebrate blood. Coelom reduced to sinuses filled with botryoidal tissue, vascular system modified into haemocoelomic sinuses. Hirudo medicinalis example historically employed for anticoagulant hirudin secretion.