A method of line fishing in depths of over 1000 fm has been used successfully from R.V. ‘Sarsia’ on the continental slope. The catches have been mainly black squaloids but two brotulids, truly abyssal fishes, have also been taken.

The number of diatoms, and the carbohydrate and organic matter in suspension, were followed during most of the year 1962 in Loch Striven.

A rise in diatom numbers was always accompanied by a rise in both carbohydrate and organic matter, but the agreement was not quantitative.

The production of larvae by Ostrea edulis L. was studied in collections made from brooding females obtained from oyster grounds on the east, south and south-west coasts of England and from the Menai Straits. The size of the brood was directly related to the size of the oyster, but considerable variation was found from oysters of the same size whether measured as diameter, volume between the shells or dry meat weight. Part of the scatter was due to variation in condition of the oyster at spawning; oysters in good condition at the time of spawning produced more eggs than those in poor condition. This cause of variation was also seen in different populations; those with a high average condition index had a higher average fertility than those in poor condition, although the correlation was not quite significant at the P = 0.05 level (r = 0.632). It is presumed that most of the remaining variation is of genetic origin.

Fertility was related to size rather than age, although it is suggested that in some old slow-growing oysters it may be reduced. No decline in fertility was found as the breeding season progressed, nor was there clear evidence that larvae are liberated at a smaller size late in the season.

A comparison of the average size of broods at an early stage of development with those that were nearly mature showed that there was no loss of larvae during brooding. Samples of shelled larvae from 204 broods were measured; less than 10 % exceeded 190 µ size.

When the oscular tube grows the spicules tend to separate from one another, but the separation is not uniform; local displacements of spicules occur with respect to other spicules in the vicinity. The same is found when the tube elongates while constricting, or changes shape in other ways. The spicule displacements reveal that the mesogloeal matrix is plastic. The spicules are probably anchored to the surface epithelia, the system of anchorage varying with time and from one spicule to another.

Small growing spicules may rotate through considerable angles and move relative to the fully grown spicules in their vicinity. The relative movements are most frequently towards the osculum. They are attributed to displacements of either the mesogloeal matrix or the internal epithelium, each relative to the other. They are not likely to be caused by the concerted amoeboid activity of the founder calcoblasts.

The monaxons tend to maintain their positions and orientations relative to the tri- and quadri-radiate spicules, apart from small localized displacements. Thus no significant movement of the pinacoderm relative to the rest of the wall could be deduced.

Fragments of broken spicules likewise tend to retain their relative positions and orientations in the spicule arrangement, though some moved or rotated by quite considerable amounts.

Spicules occasionally disappeared from the wall of some tubes. Monaxons were shed relatively easily, probably as a result of the spicule crowding associated with contraction of the tube. Some tri- and quadri-radiates were also shed through the pinacoderm. In some tubes spicule protrusion occurred at the oscular edge.

By estimating samples of diatoms taken from 0.2 m contour lines, over a horizontal range of about 85 m in the months of July 1953 a nd February 1954 the ecological factors influencing the distribution of eleven species of mud-flat diatoms were investigated. The three important factors were considered to be: the resistance to desiccation near the M.H.W.L., the ability to live under short periods of illumination near to the M.L.W.L., and the ability to tolerate the organic materials present in the black sulphureous layer. Table 7 summarizes the results for the eleven species.

Larvae of the sand-eel, Ammodytes marinus, appear in large numbers in the Southern Bight during March, some 2–4 weeks after the peak hatching period of plaice eggs. The sand-eel larvae outnumber those of the plaice about tenfold, but the factor may be 60 or more locally.

The principal food components in sand-eel guts in 1961 were copepod nauplii and appendicularians, while plaice were feeding almost exclusively on the latter. Larvae of both species show identical feeding patterns, with activity ceasing at night, and both aggregate during the day at depths of about 2–6 fm. Thus the sand-eel larvae are not separated from the plaice larvae by any pattern of behaviour, and are partially exploiting the same food reserve.

Consideration of prey size suggests that any direct competition from the larval sand-eels would first affect the smallest plaice larvae, which are in any case the most vulnerable to shortage of food. But any reduction in the crop of small appendicularians will later be reflected in the number of larger ones, and in this way older plaice larvae might be affected. While the food supply appears to have been adequate up to the time of the investigation, the reserve apparently represented only 3 days' rations. The significance of this observation is unfortunately obscured by our ignorance of appendicularian biology; but, should the food reserve become so diminished, competition between plaice and sand-eel larvae might be expected. The extent of its impact on survival is only likely to emerge from more comprehensive surveys.

The number and size of colonies found in bacterial counts of sea water collected from the Menai Straits varies with the concentration of peptone in the medium. The optimum concentration of peptone was found to be 0.3%. Neither yeast extract, beef extract or added iron increased the count when added to media made from Menai Straits water. The effect of various temperatures on the count, and the relative merits of pour plates and surface growth techniques were examined. Vigorous shaking, or passage through a Sharpies centrifuge, was found to increase the count.

A survey at Hamble Spit showed that C. tentaculata was less abundant near high water mark than farther down the shore. The influence of various environmental factors on the worms' distribution was investigated, and it was concluded that temperature, salinity, oxygen content, and water content were of minor importance. Both the particle size of the mud and its carbon content showed some correlation with the abundance of the worm. However, periodic strong wave action seemed to have the most influence on the distribution of the worm over the mudflat.

The distribution of electric rays (Torpedo spp.) in northern European waters is discussed. Torpedo nobiliana is admitted as of regular occurrence; records of occurrence of T. marmorata are given in detail. The status in these waters of T. torpedo is doubtful. A synoptic key is provided together with illustrations of the three species.

Free-swimming planktonic larvae of most species of sedentary marine invertebrates do not metamorphose in mid-water and settle at random, but possess considerable powers of delaying metamorphoses until a suitable substrate is encountered. Within recent years several workers have analysed the physical properties of a substrate to which larvae respond, particularly amongst those species which are restricted in their distribution in the littoral zone to the surfaces of other animals and plants. The serpulid Spirorbis borealis occurs most abundantly on Fucus serratus; experiments conducted in which surfaces treated with extracts of F. serratus were offered as alternatives to untreated surfaces illustrated that the larvae settle on these extract-treated surfaces in significantly greater numbers. It has been demonstrated that this response is to some chemical substance derived from the alga rather than to changes in physical properties of the surface such as increased thickness of the overlying film, or changes in the surface texture. Contact with this substance modifies the settlement behaviour from that observed amongst larvae settling on untreated surfaces. The photopositive behaviour is curtailed, and the duration of the crawling behaviour preceding settlement abbreviated. The precise mechanism by which the larvae respond to the active substance is as yet unknown, but observations have illustrated that it is dependent upon the larvae detecting the active substance as an adsorbed layer on the surface rather than a response to concentration gradients in solution. The significance of an innate ability to detect specific substrates by chemical structures characteristic of the surface in the speciation of the Spirorbinae has been discussed.

The lower limit of the Laminaria hyperborea (Gunn.) Foslie zone is probably not always determined only by lack of sufficient light, even when a suitable substratum is present (Kain, 1962). It also appears that the establishment stage is critical although growth conditions deteriorate with depth (Kain, 1963). It therefore seemed desirable to determine exactly what the light requirements of the various different early stages were, and relate these to what could be found out about the light penetration in the natural habitat. The effect of temperature on these stages is also of interest, in relation to the seasonal cycle as well as to the geographical distribution of the species. In this study two different techniques were used: culturing the gametophytes on cover-slips and also studying changes in oxygen concentration as measured by the Winkler method.

The gametophytes of the different members of the Laminariales show a similar general course of development. A zoospore from a fertile frond of a Laminaria plant loses its motility, rounds off, swells and produces a tube with another sphere at the end into which all the cell contents pass (Killian, 1911). This process can be carried through in the dark but further development depends on light (Schreiber, 1930). In this genus the gametophytes are dioecious (Sauvageau, 1918; Williams, 1921) and equal numbers of male and female plants are produced (Schreiber, 1930). The female gametophyte may become fertile before dividing further (Sauvageau, 1918), resulting in a single egg, or may form a luxuriant filamentous structure which may produce many oogonia over a period of time (Ikari, 1921; Myers, 1925; Schreiber, 1930).

Experimental studies of plankton luminosity have been made with specially designed photomultiplier equipment; this records (on a Servograph Recorder) the flashes given off either by a sample of plankton or by individual animals placed in a container in a dark observation chamber. The apparatus is described.

Apart from preliminary laboratory records on the flashing of Beroë, Pleurobrachia and Pyrosoma, and record of the general luminosity in the sea at a depth of 62 m (made with an underwater version of the apparatus), the main work has been a laboratory study of the luminescence of dinoflagellates and of the euphausiacean Meganyctiphanes norvegica.

The dinoflagellate experiments showed the inhibiting effect of light, both natural and artificial, on luminescence, and the stimulating effect of mechanical disturbance which may override the former inhibition. A rise in temperature increased luminosity and cooling reduced it. A difference in the pattern of the luminosity of plankton samples containing dinoflagellates was shown by the introduction of actively swimming animals of different kinds. The dinoflagellates in the samples were mainly Peridinium depressum, Ceratium horridum and C. tripos var. balticum.

The Meganyctiphanes experiments showed a spontaneous flashing in seventeen out of twenty-seven tests and in one test the animals maintained such activity for the greater part of a 24 h period. In addition to their bright flashing, the photophores would at times keep up a dull glow for long periods (especially see the observations of F. Körte in the Appendix). Spontaneous flashing does not only occur in the breeding season as had been suggested by Mauchline (1960).

The structure and ciliation of the lip-apparatus of two species of Lima—L. hians (Gmelin) and L. excavata (Fab.)—and one species of Pecten—P. maximus (L.)—is described.

It is suggested that the lips of these three species of bivalves have been hypertrophied (and in one case partially fused) in order to retain particulate material being carried from the ctenidia to the mouth while at the same time allowing the escape of water currents, generated by the ciliary tracts of the ctenidia and palps, from the proximal oral grooves. Such water currents must emerge from between the lips of all bivalves but do not usually interfere with the passage of particulate material. In the Limidae and Pectinidae, these water currents have been intensified by the reduction of the anterior regions of the mantle cavity. Since this change in the proportions of the body can be correlated with the evolution of the monomyarian condition in the Anisomyaria, it is postulated that the lips of all monomyarian Anisomyaria will be similarly hypertrophied.

The Preliminary Check-list (Parke, 1953), with the three subsequent lists of additions and corrections (Parke, 1956, 1957, 1959) was intended to provide a fundamental basis for the preparation of a Flora of the British marine algae sponsored by the British Phycological Society. Changes, both taxonomic and systematic, have been so numerous in recent years that a new Check-list is now necessary for the six Classes dealt with in 1953. Five additional Classes, marked below with an asterisk, are also included in the new list. As there is still controversy regarding the status and arrangement of the major algal groups they are here given, as in Parke (1953), the rank of Class.