Polycera quadrilineata with intricate black pattern. Sublittoral, 6 metres. August 2012. Whitby, Yorkshire. Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder Paula Lightfoot
Polycera quadrilineata. Yellow pigment on raised mantle rim and flanks. Grey dorsal line on anterior. Some black on gills and rhinophore stems. Yellow propodial tentacle at bottom right of image. Menai Strait. August 2010 Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata rhinophore. 15 lamellae, lower ones incomplete. Middle third flexed backwards, translucent white with yellow pigment on anterior. Distal third flexed forwards, yellow, except translucent white tip. Menai Strait, Wales. Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Length 20 mm. Reddish viscera. Patch of black on each rhinophore stem. Menai Strait, Wales. March 2010 Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Gill fan folded backwards. Body may conceal foot (right), or foot may spread laterally into view (left). On prey; Membranipora membranacea on Laminaria frond. Menai Strait, Wales. Feb. 2011. Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Length 20mm. Scarlet faeces being excreted from anus on gill-fan stem. When defecating, gill fan can be held vertically to avoid fouling of gills. White penis behind right rhinophore. Menai Strait, Wales. March 2010. Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Length 20mm. Yellow viscera. Anterior veil with four elongate yellow processes. Dorsally yellow, propodial tentacles. Semi-circular oral area with curved perpendicular white flange at each side. Menai Strait, Wales. Feb. 2011 Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Length 20mm. Apart from appendages, yellow pigment restricted to row of marks on dorsum and marks on mantle rim. Pale dull orange digestive gland below gills. White buccal mass below rhinophores. Menai Strait, Wales. Feb. 2011. Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Length 20mm. Specimen heavily marked with many black lines, yellow marks and areas of black. Menai Strait, Wales. March 2010 Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith
Polycera quadrilineata. Yellow marks on reduced mantle rim and flanks. Triangular process at rim's anterior. 7 white, simply pinnate gills, yellow distally, around dorsal anus. Anterior veil with 6 elongate yellow processes. Menai Strait, Wales. Feb.2011 Species Polycera quadrilineata (O. F. Müller, 1776) Photographer / copyright holder I.F. Smith