DORVILLEIDAE CHAMBERLIN, 1919

Dorvilleidae is a morphologically heterogeneous group, including some of the smallest described annelids with adult length of only a few hundred µm and only a few segments (Neotenotrocha). Others may attain a size up to 10 cm and have many segments (e.g. Dorvillea). The colour of live animals is variable, transparent to whitish being common (Pl. 7b–d; Fig. 31.2a), but sometimes with bright red or other pigmentation (Pl. 7a). Within Dorvilleidae, Ophryotrocha is well known through a series of studies (Sella and Ramella, 1999 and references within) for an impressive variation in mating systems. Interestingly, taxa showing no apparent morphological differentiation are separated by their differing reproductive habits. Some Dorvilleidae (e.g. Ophryotrocha) are also easily kept in culture and so provide excellent subjects for experimental studies.