Flatworm

"Like nudibranchs, marine flatworms are hermaphrodites and it's possible that the wound near the top, right-hand end of this individual is from mating, since many species mate by inserting their penis into any part of their partner's body; wherever the sperm ends up, it migrates to the animal's ovaries where fertilization happens."

Found this tiny flatworm as we are ending our dive for the day at the shallow portion of the reef. At first, I thought it was a nudibranch but upon close check, I cant find the gills. Size of the this flatworm is around 1 cm.

http://www.richard-seaman.com/Underwater/Philippines/Nudibranchs/index…