Ceratosoma tenue Abraham, 1876 (revisited)
This large and beautiful species is quite variable in color forms. It is similar to Ceratosoma gracillimum and C. trilobatum (Courtesy of Bill Rudman's Sea Slug Forum). The main differences are in the lobes along the mantles edge. C. tenue has two lobes on each side, both smaller and narrower that those of C. gracillimum and C. trilobatum. The single lateral lobes of these two latter species are much larger. This species comes in red, brown or orange. The head and lateral lobes are outlined with a purple line, which may be whole or broken as seen above. This species which may reach 120 mm in length is known from the entire western and central Pacific Oceans.