Behavioural and Secretory Activity during Tube construction byPlatynereis dumeriliiAud & M. Edw. [Polychaeta: Nereidae]

The ‘mucous’ tube ofPlatynereis dumeriliiis made up of successive layers of fine threads held together by an adhesive secretion. Tube construction involves a regular sequence of behaviour which can be modified if algae or other objects are available for incorporation into the tube wall. Anterior parapodia are specialized for tube construction and gland cells producing tube components occupy most of the coelom in these segments. Several types of gland cell can be recognized histologically and those which form the threadsdischarge into a complex spiral organ below the cuticle.