Body plan of an earthworm. Partitions (septa) divide the body cavity (coelom) into more than 100 elipsis
Any member of a phylum (Annelida) of
invertebrate animals that possess a body cavity (coelom), movable bristles (setae), and a body divided into segments by crosswise rings. Known as segmented
worms, annelids are divided into three classes: marine worms (Polychaeta;
see polychaete),
earthworms (Oligochaeta), and
leeches (Hirudinea).
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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
