HALOGENATION AND QUINONE-TANING OF THE ORGANIC TUBE COMPONENTS OF SOME SABELLIDAE (ANNELIDA, POLYCHAETA)

Histochemistry, histoenzymology, and microanalysis have been applied t o the study of tube-making in two Sabellidae (Sabella pavonina and Spi rographis spallanzanii). The investigation examined the tube constitue nts and the glands which supply them in two distinct secretory sequenc es. The organic tube adds to the wrapping of a roll which includes exo genous material gathered by the building organs and whose spiral depos it on the upper rim ensures the growth of the outer layer, with an inn er sheath elaborated by the ventral thoracic shield. This sheath is mo stly composed of sulphated glycosaminoglycans, rich in sulphur and cal cium. The wrapping of the initial roll built al the level of the paral lel folds separating the ventral lobes of the collar, comes from the t yrosine-rich superficial secretions of the collar and mainly from glan d clusters previously described. The most anterior cluster secretes a sulphur-poor proteoglycan. The roll strengthening is correlated to exo genous halogenation, thus according with the long-noticed high level o f iodine in sabellid tubes. We link this halogenation with the presenc e of a catecholase in ''Meyer's anterior gland'' secretion, suggesting quinone-tanning hardening, as well as the presence of DOPA oxidase in the shield.