The morphology and larval behaviour of a new species ofSpirorbis(Serpulidae)

Abstract

Spirorbis rupestrissp.nov. has a sinistrally coiled, unridged tube and is distinguished fromS. borealisDaudin only by colour, small morphological details and striking differences in larval behaviour. Though the larvae are capable of swimming, they do not usually do so, but crawl about and soon attach themselves to rock surfaces near the tubes of their parents, particularly when stimulated by the presence of the coralline algaLithophyllum incrustans. They will not settle onFucus serratus.S. rupestrisis found typically on rock surfaces in well-illuminated places throughout the lower half of the shore, generally associated withLithophyllum. It is abundant on the shores of south-west Britain, except where there is scouring by wave-borne particles.