A phylum of animals from Old Earth, originally with about 17,000
species. Examples are earthworms, ragworms, fanworms, and
leeches. Annelids are long soft wormlike animals, typically
composed of a number of similar segments, and lacking any
internal or external skeleton, and the original species ranged
in size from microscopic individuals less than a millimetre long
to animals as large as 3 metres in length. They were native to
moist or aquatic environments ranging from damp earth to streams
and ponds to marine intertidal, pelagic, and even hydrothermal
environments. Most commonly burrow in sediment and feed on
detritus, but some are sessile filter-feeders, predators or
herbivores in the water column, or internal or external
parasites. The original species and their various descendants
are important elements in the ecologies of habs and terraformed
worlds. Genes from annelid species native to hydrothermal vents
have been incorporated into a number of high-temperature tweaks,
human and otherwise. Annelid provo