11 Main Characteristics

The Biology 2003 Diversity of Plants and Animals custom publication for Dalhousie University provides 11 main characteristics of the phylum Annelida.
1. Body is segmented
2. Body wall with outer circular and inner longitudinal muscle layers: outer transport moist cuticle secreted by epithelium
3. Chitinous setae
4. Closed circulatory system
5. Complete digestive system, not segmentally arranged
6. Coelom well developed and divided into septa
7. Respiration through skin, gills, or parapodia
8. Excretory system typically a pair of nephridia for each segment
9. Nervous system double ventral nerve cord and a pair of ganglia with lateral nerves in each segment. The brain is a pair of dorsal cerebral ganglia with connectives to ventral nerve cord
10. Sensory system of tactile: organs, taste buds, and eyes with lenses
11. Hermaphroditic or separate sexes, larvae, if present are trochopore type, asexual reproduction by budding in some spiral cleavage and mosaic development.