This is preliminary to a series of papers resulting from SOND 1965 Cruise aboard R.R.S. ‘Discovery’. The cruise was designed as an ecological study of sonic scattering layers at a certain season in a restricted volume of ocean in the region of the Canary Islands. These papers will appear periodically in this journal.

Reproduction and feeding of Argentina sphyraena L. were investigated during a study of the biology of this species in the Clyde Sea Area of Western Scotland from 1963 to 1966.

The absorption of zinc has been studied in the brown seaweed Laminaria digitata (Huds.) Lamour., with use of the radionuclide 65Zn and atomic absorption analysis. No evidence of the regulation of zinc by the plant has been found. Absorption of zinc or 65Zn is a gradual process of accumulation which may continue throughout the life of the plant and is not accompanied by the exchange of zinc. As a result, once it has been absorbed, zinc or 65Zn shows little tendency to be lost from the plant. The amounts of zinc or 65Zn which can be accumulated from sea water containing different concentrations of zinc and the effects on these of growth, light and competition from other metals have been studied. Possible sites at which zinc might be bound have been discussed, and the experimental results have been compared with the situation found in the field.

The flash-stimulated luminescent response (FSLR) of euphausiids is a useful tool for the investigation of their bioluminescent behaviour. This paper describes the investigation of the effects of temperature upon a series of such FSLRs produced in individuals of Thysanoessa raschi (M. Sars) by three stimulations with an electronic photofiash at 20 min intervals. The following parameters of the response were measured: responsedelay, responseduration, the sum of these two {delay + duration) and the proportion of stimulations which produced a response. Initial experiments showed that all response delays were significantly different at 10°C and at 5°C, while second andthird response delays were not different from each other. The effect of a range of temperatures from 0° to 20°C on FSLR delay and duration is described. Regression lines based on the Arrhenius equation were fitted to the results. These showed that all response parameters decreased with increasing temperature, although Q10 varied from — 7.8 in the case of thefirst response delay to — 1.3 in the case of second/third response delay. This difference was the most marked effect of the second stimulation; the third stimulation caused no additional change. Below 10°C the second delay was shorter than the first delay. The independent response parameters were found to be delay and delay + duration. Duration resulted from the interaction of these two. These results are discussed and compared with the interpretation of the results of similar experiments by Kay (1965, 1966) onMeganyctiphanes norvegica.

The ostracods have been analysed from a day and night series of horizontal tows taken near the Island of Fuerteventura (Canaries). Thirty-five species were identified. Nineteen species were sampled in large enough numbers to describe their depthe distributions and the ranges of their vertical migrations. Seven species were too small to have been adequately sampled by the methods used, and the remaining nine species were too rare to draw any firm conclusions as to their depth ranges.

Deposit-feeding by Scrobicularia planaScrobiculariaplana (Da Costa) along the mud surface occurs throughout the period of low tide if the water table remains at the surface. The rate of deposit-feeding is unaffected by the time after emersion at low tide except where excessive drainage prevents feeding along the mud surface, in which case it is possible that animals feed from the sides of their burrows at or below the level of the water table.