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
©RLLord sealordphotography.net
fishinfo@guernsey.net
This humpback scallop, Chlamys distorta, is attached to the base of a granite boulder on the lower shore in Belle Greve Bay on Guernsey's east coast.  As an adult the right valve of this scallop is cemented permanently to the substrate it attaches to.  This individual had a shell length of about 3 cm.  It was photographed on the 8 February 2008.
File No. BG 080208 2908
©RLLord
fishinfo@guernsey.net
I visited the fish quay pontoons in St. Peter Port harbour on the 18th September and found three large Janolus cristatus nudibranchs but I didn't photograph them.  On the 21 September I revisited the pontoons and saw this tiny Janolus cristatus individual that probably wasn't much more than 10 mm long.  Janolus cristatus feed on bryozoan colonies and particularly the erect Bugula colonies.  They also lay their strings of pearl-like egg cases on their food.  

File No. 210907 1102
©RLLord
fishinfo@guernsey.net
This bryozoan colony, Watersipora subtorquata, was discovered in the Queen Elizabeth II marina, St. Peter Port harbour, Guernsey, Channel Islands on 30 May 2007.  It was growing attached to the south side of a pontoon next to the south wall of the marina.  This species is an invasive species that probably arrived on a boat's hull from France.  It is native to the western Atlantic and the Caribbean.  It has already been introduced to the Californian coast of the Pacific Ocean.  This image shows the feeding lophophores extended.  This specimen was identified by John Ryland, Emeritus Professor of Marine Biology at the University of Wales Swansea, and Dr. Joshua Mackie of the Moss Landing Marine Laboratories, California, USA.
File No. 300507
©RLLord
fishinfo@guernsey.net
This colony of the bryozoan Watersipora subtorquata is the first record of this species in the British Isles.  It was found growing on the south side of a pontoon running along the southern wall of the Queen Elizabeth II marina in St. Peter Port, Guernsey, Channel Islands on 30 May 2007.  John Ryland, Emeritus Professor of Marine Biology, from the University of Wales Swansea and Dr. Joshua Mackie from Moss Landing Marine Laboratories in California identified the species for me.  This species may have been found since the initial discovery in Plymouth, England by Dr. John Bishop on the hull of a beached ship.  This species is native to the western Atlantic and the Caribbean.
File No. 300507 20-907 
©RLLord
fishinfo@guernsey.net
Ross coral, Pentapora fascialis, grows in the Little Russel, which is the sea channel between Guernsey and Herm off Guernsey's capital, St. Peter Port. The zooids form heavily calcified bilaminar plates that intersect to produce a three-dimensional solid but brittle structure that resembles a coral head (phylum cnidaria) hence the common name.  This colony was growing on a cobble on the seafloor. It had a width of about 30 cm.  These colonies can live 12 years. It was photographed on 11 July 2004.
File No. 110704 13-745
A close-up view of zooids of the bryozoan, Flustrellidra hispida, which was growing on the surface of the brown seaweed, serrated wrack, Fucus serratus, at La Valette on Guernsey's east coast on 1 August 2003.  Some of the zooids have extended their lophophores (bell-shaped ring of ciliated tentacles) to feed.
File No. 010803 13-682
©RLLord
fishinfo@guernsey.net
The ctenostomatid bryozoan Flustrellidra hispida growing on the brown seaweed, serrated wrack, Fucus serratus.  The close-up image shows the kenozooid spines and the expanded feeding lophophores.  Collected from La Valette on Guernsey's east coast on 1 August 2003.
File No. 010803 13-682 
©RLLord
fishinfo@guernsey.net
Schizoporella unicornis lophophores LaV 170603 29-677 smg
This bryozoan colony, Watersipora subtorquata, was discovered in the Queen Elizabeth II marina, St. Peter Port harbour, Guernsey, Channel Islands on 30 May 2007. It was growing attached to the south side of a pontoon next to the south wall of the marina. This species is an invasive species that probably arrived on a boat's hull from France. It is native to the western Atlantic and the Caribbean. It has already been introduced to the Californian coast of the Pacific Ocean. This image shows the feeding lophophores extended. This specimen was identified by John Ryland, Emeritus Professor of Marine Biology at the University of Wales Swansea, and Dr. Joshua Mackie of the Moss Landing Marine Laboratories, California, USA.
File No. 300507
©RLLord
fishinfo@guernsey.net
This bryozoan colony, Watersipora subtorquata, was discovered in the Queen Elizabeth II marina, St. Peter Port harbour, Guernsey, Channel Islands on 30 May 2007.  It was growing attached to the south side of a pontoon next to the south wall of the marina.  This species is an invasive species that probably arrived on a boat's hull from France.  It is native to the western Atlantic and the Caribbean.  It has already been introduced to the Californian coast of the Pacific Ocean.  This image shows the feeding lophophores extended.  This specimen was identified by John Ryland, Emeritus Professor of Marine Biology at the University of Wales Swansea, and Dr. Joshua Mackie of the Moss Landing Marine Laboratories, California, USA.
File No. 300507
©RLLord
fishinfo@guernsey.net
This bryozoan colony, Watersipora subtorquata, was discovered in the Queen Elizabeth II marina, St. Peter Port harbour, Guernsey, Channel Islands on 30 May 2007. It was growing attached to the south side of a pontoon next to the south wall of the marina. This species is an invasive species that probably arrived on a boat's hull from France. It is native to the western Atlantic and the Caribbean. It has already been introduced to the Californian coast of the Pacific Ocean. This image shows the feeding lophophores extended. This specimen was identified by John Ryland, Emeritus Professor of Marine Biology at the University of Wales Swansea, and Dr. Joshua Mackie of the Moss Landing Marine Laboratories, California, USA.
File No. 300507
©RLLord
fishinfo@guernsey.net
See photo in original gallery.