Nudibranch (Clade Nudibranchia)

        

Funeral Nudibranch

The Nudibranch, previously classified as a gastropod, is a small shell-less organism often mistaken as a sea slug. Through the course of evolution, Nudibranchs have lost their shells in exchange for defense mechanisms. Several adaptations include mimicking their surroundings for camouflage and the bright coloring of their bodies to warn predators of the distaste of eating them. Nudibranchs usually deploy chemical defense mechanisms to incapacitate their predator thus escaping death. Nudibranchs are known to be poisonous.They have an exposed gill on their backs, which is shaped like a plume or a flower.

   Being slow moving and small, these critters often feed on corals, anemones, sponges and other small, immobile organisms. Many species have a rough tongue(radula) which contain specially adapted "teeth" which aid the Nudibranch in scraping its prey. Some species, however, choose to simply secrete digestive enzymes onto its prey and suck up their remains. We found these specimens at Pulau Semakau landfill in Singapore, hiding in the littoral zone.

ref: http://www.wildsingapore.com/wildfacts/mollusca/nudibranchia.htm

http://en.wikipedia.org/wiki/Nudibranch