ABSTRACT
Most parasitic polychaetes are endoparasites (Fig. 16), either inhabiting the tissues of their hosts (e.g. Alciopina parasitica, Dorvillea sociabilis, Branchiosyllis exilis, Autolytus penetrans, Myrianida pinnigera, Typosyllis extenuata), the peri-intestinal blood sinus (e.g. Haematocleptes terebellidis), the coelomic cavities (e.g. Ophryotrocha puerilis, Veneriservia pygoclava, Oligognathus bonelliae, most oenonids parasitizing polychaetes), the aquiferous system (e.g. Haplosyllis spongicola), the hydrothecae (e.g. Proceraea sp.) or special galls formed by the host because of the presence of the parasite (e.g. Ophiuricola cynips). With the exception of Autolytuspenetrans and the last three species, no special morphological, structural or behavioural reactions to the presence of the parasites in their hosts has been described.
