More than twenty species of oligochaeta belonging to the families Enchytraeidae, Naididae, Tubificidae and Lumbriculidae were found in the phreatic water of the river bank gravels. Psammoryctes barbatus, Rhyacodrilus coccineus and Styludrilus heringianus were found throughout the year, attaining maturity in the spring. These three species may be univoltine under these conditions. The family Naididae and a few species of Tubificidae show well marked seasons of abundance, chiefly in the summer and autumn.
Studies on the biology of oligochaetes from the phreatic water of an exposed gravel bed.
International Journal of Speleology,
Available at: http://scholarcommons.usf.edu/ijs/vol3/iss3/10