Segmented Worms

Segmented worms belong to the phylum Annelida, defined by a body divided into repeating ring like segments, each often carrying its own set of muscles, nerves, and excretory organs. The phylum spans earthworms that condition soil on land, bristle worms and tube worms that live on the seafloor, and blood feeding leeches found in fresh water and moist habitats worldwide. Many marine annelids bear paired bristled appendages called parapodia used for movement and gas exchange, while earthworms and leeches have smooth, unsegmented looking exteriors that still show internal segmentation. Some deep sea tube worms host bacteria that convert chemicals from hydrothermal vents into food, letting them live without a mouth or gut as adults.