Phylum Annelida

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Phylum Annelida

• Segmented Worms

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Annelids include earthworms, leeches, and
polychaetes
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Phylum Characteristics

• Worldwide
• Coelom is well developed
• Closed circulation
• Complete digestive system
• Nephridia for excretion

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Phylum Characteristics

• Nervous system includes sensory organs
• Respiration occurs through skin, gills, or
  parapodia (paired appendages with capillaries)

parapodia
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Phylum Characteristics

• Hermaphrodites or separate sexes
• Often called Bristle worms. The bristles are
  called setae
• Grooves indicating segments are called annuli

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Phylum Annelida
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Clitellum

• Distinct band on external surface of Oligochaeta
  (earthworms) and Hirudina (leeches)
• Secretes mucous to hold two worms together during
  reproduction

clitellum
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Polychaetes
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Oligochaeta
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Hirudinea