I think this flatworm is Cycloporus papillosus. Two individuals were lying on a large colony of the compound ascidian Botryllus schlosseri, on the base of a rock, just south of the Lihou Island causeway. This flatworm was photographed having glided off the ascidian colony on the 9 May 2009. The Botryllus schlosseri colony had been excavated and several deposits of very small eggs were deposited in the depression. I do not know if the flatworms produced the eggs or some other species such as a mollusc.
File No. 090509 3943
flatwormcycloporus papillosusbotryllus schlosseriGuernseyLihouRamsarChannel Islands9 May 2009bryozoanbryozoaGuernsey west coastmarine lifesea shorecoastinter tidalrock poolingtide poolingseashoresealordphotographymarine life photographymarine invertebrate