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It has around 120–170 segments, often 135–150. The body is cylindrical in the cross section, except for the broad, flattened posterior section. Head end dark brown to reddish brown lateral, dorsal pigmentation fading towards the back. [1] The worm has a hydrostatic skeleton and moves by longitudinal and circular muscular contractions.
Earthworms store their partners' sperm in spermathecae ("sperm stores") and then the clitellum produces a cocoon that collects ova from the ovaries and then sperm from the spermathecae. Fertilization and development of earthworm eggs takes place in the cocoon. Leeches' eggs are fertilized in the ovaries, and then transferred to the cocoon.
The genus Lumbricus contains some of the most commonly seen earthworms in Europe among its nearly 700 valid species. [2] Characteristics of some commonly encountered species are: Lumbricus rubellus is usually reddish brown or reddish violet, iridescent dorsally, and pale yellow ventrally. They are usually about 25–105 mm in length, and have ...
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The first body segment (segment number 1) features both the earthworm's mouth and, overhanging the mouth, a fleshy lobe called the prostomium, which seals the entrance when the worm is at rest, but is also used to feel and chemically sense the worm's surroundings. Some species of earthworm can even use the prehensile prostomium to grab and drag ...
The clitellum is part of the reproductive system of clitellates, a subgroup of annelids which contains oligochaetes (earthworms) and hirudineans (leeches). The clitellum is a thick, saddle-like ring found in the epidermis (skin) of the worm, usually with a light-colored pigment. To form a cocoon for its eggs, the clitellum secretes a viscous ...
The worms require loose soil to burrow in and soil moist enough for gas exchange. [3] Further requirements include such abiotic factors as pH and temperature. Various abiotic factors are significant to Lumbricus rubellus . pH is of particular importance; a range of 5.5 to 8.7 is acceptable with a preference for neutral soils. [ 4 ]
A chaeta or cheta (from Ancient Greek χαίτη (khaítē) 'crest, mane, flowing hair'; pl. chaetae) is a chitinous bristle or seta found on annelid worms, although the term is also frequently used to describe similar structures in other invertebrates such as arthropods.