Michaelsen, 1889b
Type species Enchytraeus ventriculosus D'Udekem, 1854
Number of species about 45. Three species known from fresh waters of NWE:
Henlea nasuta (Eisen, 1878)
Henlea perpusilla Friend, 1911a
Henlea ventriculosa (D'Udekem, 1854)
Several other species of Henlea have been recorded from soil but not yet from water, in NWE.
Description
Small to large enchytraeids, most often yellowish. Chaetae numerous, arranged in symmetrical fan-like bundles. Male pores in XII. Internal characters: Pharyngeal glands in three pairs, without dorsal communications or ventral lobes. Oesophagus expanding abruptly into intestine at 7/8; intestinal appendages usually present at this point, and oesophageal appendages in IV-VI. Blood colourless, dorsal blood vessel limited to anteclitellar region. Spermathecae in V, without diverticula or glands, communicating with oesophagus. No seminal vesicles, no egg sacs. Characterized, in comparison with other genera, by symmetrical fan-like chaetal bundles, and a selection of internal characters as appendages of digestive tube, simple spermathecae, etc. However, somewhat similar chaetal bundles can occur also, e.g. in several small worms from the genus Marionina.
Burrowing in sediment.
Distribution
Mostly Holarctic, with scarce findings from mountainous habitats of other regions.
Ecology
In soil and freshwater.
Reproduction
Sexual only, with eggs laid in cocoons.
Literature
Michaelsen, 1889b: 31; Nielsen and Christensen, 1959: 55-58; Chekanovskaya, 1981: 375; Kasprzak, 1986: 254-255.