Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 16 families within the order; they are thought to have a cosmopolitan distribution in tropical and temperate waters worldwide.
Octopus Eye - However underwater light has a polarized component which some octopuses can detect. When this light travels through the body of a transparent animal its polarization will be changed and the octopus can see that and capture the prey.
Starfish by Leon Heyns Underwater shot of a starfish. Shows the underside as well. Due to the depth, color is different underwater and the under-side of the starfish appear more green than the original yellow and red on the top-side.