Hirudo leech: Segmented worm of the Phylum Annelida species, with anterior and posterior suckers, hermaphrodites, it explores it's water environment and feeds on its host injecting anti-coagulents to assist predation and, when gorged with blood, it falls away.
Hirudo gigantae vulgaris: these huge, marsh emergent, leeches are now wholly terrestrial in form. They feed on development sites, inject capital and rapaciously extract huge value from their hosts at the expense of future generations. They favour brownfield and, increasingly, greenfield land. When gorged they fall away and move on in search of new opportunity sites.