Leeches

Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodies that can lengthen and contract. Both groups are hermaphrodites and have a clitellum, but leeches typically differ from the oligochaetes in having suckers at both ends and ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid; the coelom, the spacious body cavity found in other annelids, is reduced

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species of annelid

Acanthobdellidea is an infraclass of primitive leeches; some authors place them in a separate subclass from the Hirudinea. However, the World Register of Marine Species places them within the Hirudinea, as a sister group to Euhirudinea, the true leeches.

Euhirudinea, the true leeches, are an infraclass of the Hirudinea.

species of annelid