Ein Beitrag zur Morphologie, Biologie und systematischen Stellung des Polychaeten Ctenodrilus serratus

Abstract

The drilomorph polychaete Ctenodrilus serratus (O. Schmidt 1857) is described. The following features are variable: size, colour of epidermal glands, number of bristles within one bundle, shape of bristles. According to these criteria C. s. limulicolus is not a valid subspecies. The pharyngeal bulb (buccal bulb) of the ctenodrilids can be compared with that of the archiannelids; it cannot be homologized with the buccal bulb of the genus Potamodrilus (Oligochaeta). This pharyngeal bulb is important for feeding and movement. C. serratus and the other members of the family Ctenodrilidae have a ventral ciliary field on the first segments, which has apparently no function for feeding and locomotion. The presence of this field and the epidermal glands, as well as the absence of paired tentacles and gills enable the Ctenodrilidae to be separated from the Cirratulidae. © 1973 Biologischen Anstalt Helgoland.