1. 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.
  2. 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.

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.