An earthworm is a tube-shaped, segmented worm found in the phylum Annelida. Earthworms are hermaphrodites: each individual carries both male and female sex organs. As invertebrates, they lack either an internal skeleton or exoskeleton, but maintain their structure with fluid-filled coelom chambers that function as a hydrostatic skeleton. Earthworm is the common name for largest members of Oligochaeta which either class subclass depending author. Dew-worm, rainworm, night crawler, angleworm. Larger terrestrial earthworms are also called megadriles which translates to big, opposed microdriles small worms semiaquatic families Tubificidae, Lumbricidae, and Enchytraeidae, among others. Larger Lumbricus terrestris worms crawl greater absolute speed than smaller. They achieve this by taking slightly longer strides but with slightly lower stride frequencies. 4K 3840×2160.