Gold has been determined in six marine sponges by neutron activation analysis. The amounts found (1·8–12·6 × 10−8 g/g dry sponge) are higher than would be expected from measurements of the distribution of 198Au between sea-water and dead sponge samples.

Many attempts have been made to devise methods for concentrating gold from sea water, but none of them are commercially viable. Recent work has shown that gold can be concentrated by adsorption or absorption on certain artificial polymers (Hummel, 1957; Bowen, unpublished). This note describes some measurements of the accumulation of gold by marine sponges whose scleroprotein structure resembles some of the artificial polymers employed.

Off the coasts of the Eastern Aegean Island of Chios underwater observations were made on the labrid Crenilabrus (= Symphodus) ntelanocercus (Risso).

It was found that undisturbed observation could be made from 4 to 5 m away from the fish's territory, but if closer, then diver-orientated behaviour occurred. The fish might inspect the diver, or if alarmed, show fright reactions of different intensities. Conflict situations for the fish sometimes resulted in displacement chaffing. Pursuit caused the fish to show a series of escape reactions depending upon the intensity and persistence of the pursuit. Initially the fish showed avoidance reactions by fleeing or following set ‘escape routes’; further pursuit caused it to hide among the eel-grass, Posidonia; and finally aggregation and flight were resorted to.

The iron nutrition of Phaeodactylum tricornutum (Bohlin) has been studied, and the limitation of growth because of iron deficiency demonstrated. Evidence is presented suggesting the ability of the organism to utilize paniculate iron and to adjust its utilization of iron in the presence of a continuing deficiency. One effect of lack of iron is a reduction in the degree of pigmentation and the ability of added iron to restore the pigmentation. Figures are presented showing the iron content per cell, and a comparison with other organisms suggests that the brackishwater P. tricornutum may be atypical when compared with coastal and oceanic members of the marine phytoplankton.

Concentrations of zinc and copper have been measured in 18 species of decapod crustaceans, ranging from freshwater to purely marine species. Although the intake of zinc and copper probably varies considerably, the majority of animals contain between 20 and 35 μg/g of both metals. This is probably because the concentrations in the body fluids and tissues are regulated. Reasons for differences between the concentrations of zinc and copper in the individual tissues of different species are discussed and the ways in which regulation is achieved are compared.

Various enzymes have been successfully localized in whole specimens of several groups of marine animals up to 5 mm body thickness. With certain exceptions the animals are fixed for a short time and then incubated in media modified from those designed for sections. After incubation the specimens are stored in fixative or buffer for later serial sectioning back at the laboratory.

Three hundred and thirty-one turbot and 350 brill of varying ages were examined for infection with the tapeworm Bothriocephalus scorpii (Müller, 1776).

This survey showed that: (i) turbot and brill acquired infections of B. scorpii before they were 1 year old; (ii) all the adult turbot were infected with B. scorpii, often heavily, whereas only half the adult brill were infected and then only slightly; (iii) differences in the structure of the gut mucosa could account for the strong attachment of the scoleces in turbot compared with the loose attachment in brill.

The intertidal algae Enteromorpha, Ulva, Fucus, Porphyra, Chondrus and Griffithsia are subjected to wide semi-diurnal fluctuations in temperature during the summer months. Measurements of the rate of respiration of such algae in the dark at a wide variety of temperatures have shown that during the summer the curve relating respiration to temperature (R. T curve) has a relatively shallow slope of Q10 < 1·2 between 10° and 20 °C. Algae collected during the autumn and winter show R. T curves which have a shallow slope in regions approximating to the temperature of the shore at the time of collection. Thus the respiration of such intertidal algae is relatively unaffected by temperature fluctuation within the normal environmental range. Further, the form of the R. T curve is not a fixed phenomenon which is characteristic of a particular species of alga, but appears to be modifiable in such a way that the shallow region of the R. T curve is appropriate to the temperatures prevailing in the habitat. In this way the effects of temperature fluctuation upon respiration are minimized.

The intertidal actinian Anemonia sulcata is known to harbour yellow-brown algal symbionts which are similar in appearance to the zooxanthellae of hermatypic, or reef-building, corals and a number of other invertebrate species. The cytochemistry and structural morphology of the zooxanthella has been studied by light and electron microscopy, to help define it taxonomically and to reveal something about its relations with the actinian. These investigations confirm that it is a dinoflagellate and have revealed several structural adaptations which are formed as a result of the peculiar mode of life adopted by this alga. Of significance is the fine structure of the periplast, which may have a considerable bearing upon the type of relationship which can exist between the host and its symbiont. These findings are discussed in terms of other known instances of algal-invertebrate symbiosis.

The rate of growth of larvae of Sabellaria alveolata (L.) reared in the laboratory varied greatly between different rearings and between individuals of the same age in the same rearing vessel, the temperature throughout being maintained close to 15 °C. The shortest recorded time from fertilization to metamorphosis was 6 weeks, the longest nearly 8 months. Within any one rearing some larvae metamorphosed weeks or months earlier than the last to do so. The larvae were fed on phytoflagellates, especially Isochrysis galbana, and the variations in growth were partially due to differing quantities of food available and to the differing character of the food. The largest larvae obtained, up to 700 μ long, fed in their later stages on an Olisthodiscus sp., alone or with another flagellate. The smallest larvae, only about 400 μ long, ate voraciously large quantities of the coccolith Coccolithus huxleyi. The normal length of larvae fed on Isochrysis alone was about 500 μ.

Using larvae reared from artificial fertilizations in the laboratory, often for several months, many experiments have been made on factors promoting settlement of Sabellaria alveolata (L.). When at last able to metamorphose after many weeks of pelagic development, the larvae of this species crawl actively over any solid surfaces with which they happen to make contact, seeking indicative characters distinctive of their normal adult environment. If these are not found at once the larvae are able to postpone metamorphosis for weeks if necessary, remaining in a developmental state able both to swim and to crawl. If delayed too long in reaching a favourable environment some may metamorphose in the absence of normal environmental stimuli, others often become incapable of metamorphosing normally and do so abnormally, or they may die without metamorphosing.

Paraphysomonas cribosa n.sp. possesses two unequal flagella, one short and smooth, the other long, bearing numerous fine hairs. The cell surface is covered with scales which are resolvable using the electron microscope. These are polymorphic, built of rods and generally having an oval periphery. Struts from this support an inner oval ring, and further struts support a central perforated area.

A study of the effects of salinity on the distribution and abundance of the amphipod Corophium volutator (Pallas) on the estuary of the River Ythan, Aberdeenshire, indicates that 2‰ is a critical minimum salinity controlling its distribution. In areas with salinities between 2 and 5‰ C. volutator was present, but in reduced numbers. Breeding occurred only in salinities greater than 7·5‰. In areas with salinity greater than 5‰, the distribution and abundance of C. volutator were controlled by the nature of the substrate; however, in areas with suitable substrates, but where the salinity was below 5‰, the effects of salinity override the effects of the substrate. The annual life-cycle is discussed. The results of this study are compared with those of a recent experimental study.

The general biology of Erythrops serrata (G. O. Sars) and E. elegans (G. O. Sars) is described. There are two main generations of E. serrata, a spring and a summer one, produced during the year although continuous breeding at lower intensities is present in the population between the most productive periods; females carry 14–18 young per brood in the spring and summer but these numbers decrease to 4–8 in winter broods. The marsupium of E. serrata is often lost after the brood emerges. The few data available for E. elegans suggest that its breeding behaviour is similar to that of E. serrata but fewer young per brood appear to be produced by this species. Both species feed on the surface layers of the bottom and the material in suspension, but E. serrata had, on occasion, remains of crustaceans among its stomach contents, indicating a carnivorous diet.

The symbiotic condition of Convoluta roscoffensis has been resynthesized in vitro by feeding new-born colourless larvae with various clones of Platymonas convolutae Parke & Manton available in culture. Greening has also been brought about by feeding larvae with other species distinguishable from the natural symbiont by pyrenoid characters, but subsequent growth of the greened larvae was less and the length of time required for greening greater. The minimum presentation time effective in initiating greening with alien symbionts in 100% of tested larvae was also greater. Cell multiplication of successful symbionts is mitotic, division stages being demonstrated in sections of worms with different types of symbiont. When cultures of potential symbionts were made available competitively in pairs, greening normally involved only one member of a pair, success being apparently determined by the order of relative efficiency demonstrated in the single-culture infections. A chimaeral condition, with two different symbionts present together, was produced and is demonstrated—but only as a temporary phase in an experiment designed to give an alien symbiont a very long start before admitting the real one. In this experiment effective greening with Prasinocladus marinas did not impede prompt entry of Platymonas convolutae when it was supplied, and this was followed by rapid and complete elimination of the alien symbiont. An interpretation of these various findings is discussed in a preliminary way.

From 1964 to 1967, 163 deep-sea fish have been caught from 28 line hauls in depths of from 1000 to 3300 m. Slightly over half the total catch consisted of elasmobranchs. The largest individual fish was a shark Pseudotriakis microdon of 2·25 m length taken from 1400 m. The distribution of the eleven species taken regularly in these and previous hauls is compared and contrasted.

A modified volumetric respirometer was constructed for an extended series of precise determinations of the respiration of small aquatic animals. Food could be introduced and all operations could be carried out without disturbance to the animal. Provisions were made for the introduction of filtered, bacteria-free sea water between experimental runs. The advantages of the volumetric technique were combined with those of a running-water system to allow the continuous measurement of oxygen consumption under controlled conditions.

A study of nineteen species of monotocardian veligers belonging to eight different superfamilies reveals the uniformity of structure of the alimentary tract up to the time of metamorphosis. Results of feeding experiments with nineteen species of unicellular algae show that there is also uniformity in the functioning of the gut.

The fatty-acid compositions of tissue lipids of Asterias rubens L., Echinus esculentus L. and Holothuria forskali Delia Chiaje were determined by means of gas-liquid chromatography. Considerable proportions of branched-chain, normal odd-numbered and eicosatetraenoic acids occur in the latter two animals. Tissues of all three animals were incubated with 1−14C-acetate. The relative specific activities of fatty-acid fractions isolated by thin-layer chromatography upon AgNO3-impregnated silica gel G fell in the order: saturates > monoenes — dienes > polyenes. The fatty-acid compositions of the alkoxydiglyceride, triglyceride and phospholipid classes of A. rubens hepatic caecal lipid were also determined.

The effect of temperature on the rate of reaction catalysed by crude muscle AMP-aminohydrolase from two species of elasmobranch and two species of teleost fish has been investigated at low substrate concentration in the range of temperature 5–50 °C.

The enzyme from teleost fish shows a very broad temperature optimum around 30 °C. The reaction rate of the enzyme from elasmobranch fish is strongly dependent on temperature. The optimum temperature for the enzyme from thornback ray lies around 40 °C. Both crude and 500-fold purified AMP-aminohydrolase from thornback ray show the same temperature-dependence.