Records of Bioluminescence in the Ocean

DURING THE MONTH of June, 1955, while measurements were being made of the depth of penetration of moonlight into the sea off the Kona Coast (S. W. coast) of the island of Oahu in the Hawaiian gtoup, some information was obtained on bioluminescence in deep water in this region and on the effect of moonlight on the vertical distribution of luminescent organisms. Observations of bioluminescence were also made off San Diego, California, during the month of January, 1956. An underwater photometer (Kampa, 1955; Snodgrass et al., 1957 in press) designed for work in the deep sonic-scattering layers was used for these measurements. This was ,equipped with a depth-indicator (Boden et al., 1955) so that a precise knowledge of the depth of the instrument was available at all times. The instrument utilizes a 931-A photomultiplier tube oriented with the sensitive surface facing up. In front of this is a collimating tube at the base of which is a filterholder for interference filters. The collimator ensures that the 5° useful angle of the filters