Phalangoverms (Finger Worms)
The phalangoverms are segmented marine worms. Each segment has a pair of fleshy chitinous "finger"-like bristles. The paddle-like highly vascularized "fingers are used for movement and as primary respiratory surfaces (as a sort of external gill. Most phalangoverms tend to have well-developed sense organs and jaws, while others lack them but may have specialized gills or tentacles used for respiration and deposit or filter feeding, e.g., fanworms. A few species have evolved to live in terrestrial environments, having evolved cutaneous invaginations for aerial gas exchange.
Some phalangoverms are notable for adaptations to harsh environments. These include hydrothermal vents, methane clathrate deposits, and cold seeps.