Siddall, Mark E. Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York.
- General morphology
- Alimentary morphology
- Reproductive anatomy
- Socioeconomic importance
- Links to Primary Literature
- Additional Readings
The leeches, classified as an order of worms in the phylum Annelida, although previously considered one of three classes (Hirudinea) on equal rank with Oligochaeta and Polychaeta. Anatomically, all leeches possess a clitellum employed in the secretion of their egg-case “cocoons,” like the prominent “saddle” seen on earthworms, and DNA sequence data confirm that leeches are related closely to the lumbriculid oligochaetes. Thus, Hirudinida is considered now to be an order in the class Clitellata, along with the oligochaetous orders. There are two suborders within Hirudinida—Arhynchobdellida (leeches that lack a protrusible proboscis) and Rhynchobdellida (leeches that possess a protrusible muscular proboscis). See also: Annelida; Arhynchobdellae; Oligochaeta; Polychaeta; Rhynchobdellae
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