Description:-

When the live worms were placed under a coverglass on a slide they are seen to be extremely contractile, rapidly altering their shape, now short and contracted, soon long and extended. In the preserved condition, the first specimen having no budding region measured 15mm in length and 0.5mm in diameter and the second specimen with two budding regions (three individuals) measured 23mm in length and 0.65mm in diameter; the former having 45 segments and the latter having 95 segments preceding a short unsegmented posterior region. The body is light reddish brown in colour owing to the presence of dark brown pigments aggregated more toward the anterior region. Prostomium rounded in shape, margin of which is also pigmented. Gills present nearly on all segments beginning from VI as paired cylindrical dorso-lateral structures. Longest gill measured 0.15 to 0.20mm and shortest 0.20 to 0.05 mm in length. In some segments they are present only on one side and in some others they are completely absent. Smaller gills intercalate with the longer gills in the anterior region. In the posterior region however gills are entirely composed of smaller ones. They contain vascular loops composed of an afferent and efferent vessels, the two vessels being connected by capillaries. Setae arranged in four bundles per segment, two ventral and two dorsal. Ventral bundles commence from the second segment and bear four setae per bundle. Setae sigmoid, nodulus distal with distal prong longer, thinner and a little bent toward the proximal. Dorsal bundle beginning from the VI segment onwards and consists of hairs and needles. The hairs are smooth and straight divisible into two types namely ordinary hairs and enclosed hairs. The former is usually associated with shorter gills projecting out of it while the latter is associated with larger gills and do not project from the surface as they are situated within the gills as an internal support, the usual number of hairs being three in the present case. Three hairs arise as separate ones at the basal region and as they enter the gills, they unite giving the appearance of a single hair seta. Of these, the longest one reaches the tip of the gill. The needles are rather straight and single-pointed. In the posteriormost region where the hair setae are absent, the dorsal bundle is composed of one needle seta alone. Asexual reproduction was seen to be taking place in one individual, the first budding zone being noticed behind XXXVIII segment.

Threats:-

Not recorded.

Remark:-

Habitat:-

This species inhabits foul smelling sediments at the bottom of tanks and also attached to the ‘roots’of Salvinia.

Synonyms:-

Lahoria hortensis Stephenson, 1910
Branchiodrillus hortensis (Stephenson) Stephenson, 1912
Branchiodrillus hortensis (Stephenson) var. japonicas Yamaguchi, 1938
Branchiodrillus hortensis bifidus Liang, 1958

References:-

Sobhana, S. 1982. Studies on the biology of the aquatic oligochaetes of Kerala. MPhil Thesis submitted to University of Kerala. Dep.t of Aquatic biology and Fisheries.