Lumbriculus variegatus

Lumbriculus variegatus, also known as the blackworm or California blackworm, is a species of worm inhabiting North America and Europe. It lives in shallow-water marshes, ponds, and swamps, feeding on microorganisms and organic material. The maximum length of a specimen is 10 cm (4 in). Worms raised in laboratory environment are slightly shorter, with 4 to 6 cm (1.57 - 2.36 in) long bodies. An adult individual has approximately 150 to 250 1.5 mm wide segments, each of which has the ability to regenerate into a new individual when separated from the rest of the animal. In most populations, this is the primary mode of reproduction, and mature individuals are exceedingly rare; in large areas (including Asia, most of North America and the greater part of Europe) mature individuals have never been found. The name blackworm is given to at least three distinct species of worm that are identical in appearance and were once considered a single species.