Warty Comb Jelly

Mnemiopsis leidyi, a comb jelly from the western Atlantic coast, lit by a photographer's lamp. The rainbow running down its sides is a famous mix-up: that is ordinary light scattering off eight rows of beating hair-like plates, and it shows in daylight too. The real bioluminescence is quieter. Light-making cells lie beneath those same comb rows, and in the dark a jostled comb jelly gives off brief blue-green flashes, which is why it is one of the creatures that sparkles in a swimmer's wake on summer nights.