Comb jellies (ctenophora) are gelatinous animals able to swim using cilia arranged in rows along their bodies. The complex animals have muscle tissue, and nervous and digestive systems. Most ctenophores are bioluminescent. In addition, there is a rainbow effect at the comb rows caused by the scattering of light. This Leucothea multicornis was photographed in about 5 metres depth at the Serra de Tramuntana, Mallorca.