The two luminous fishes Anomalops and Photoblepharon have a large luminous organ half-moon in shape located below the eye. The former can shut off display of luminescence at will, by rotating the organ, and the latter extinguishes light by a black membrane covering the luminous surface just like the eyelid does. Both fishes can be seen all the year in dark night, but don't appear in the moon-lit night.

The cultivation of luminous bacteria from the luminous organs of these fishes were tested, and variations were observed in the light intensities of the sea water emulsions of the luminous organs according to effects of salt, temperature and chemicals respectively.

The result of the test cultivation was negative. However, summarising the results of the experiments; the contents of luminous body of the two fishes are luminous bacteria, which were recognized clearly in the electron microscopic.