While not technically a nudibranch, Flatworms are still a fun find!

Technical Data: Canon EOS 7D, Canon EF 100mm f/2.8L Macro IS USM, 1/120th sec at f/4.5. ISO 1250. Ikelite Housing and Port with dual Ikelite 161 Strobes. Raw conversion in Adobe Camera Raw.

This is apparently a juvenile Lined Flatworm (Pseudoceros crozieri) - I was confused on the identification until a bit of research turned up that the juveniles of this species have that orange border that will fade as they grow into an adult (and that tidbit of information is lodged in my brain forever now!).

- Bill