(From Wikipedia, November 3, 2010)
– – –
The body of this nudibranch is translucent white. There are up to seven orange tipped processes on each side of the gills. A pair of longer processes project forwards from the base of each rhinophore. White ovotestis is visible through the transparent epidermis. The oral tentacles are short and tipped with orange. Orange pigment is also found on the tips of the rhinophores and on the tip of the tail. Occasional individuals can be found in which the orange pigment is replaced with white. Adult specimens may reach a length of 33mm. There are several other species with similar coloration including Polycera quadrilineata,Polycera faeroensis and Trapania maculata.
(From EOL via Encyclopedia of Marine Life of Britain and Ireland, November 3rd, 2010)