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.

Stocks of adult female Pseudocalanus elongatus have been kept for the past 6 years in a laboratory remote from the sea. The techniques used in maintaining these stocks are described.

The most suitable temperature for keeping the copepods has been found to be 10 °C.

The control of pH has not been necessary.

Although an allowance of 30 ml. of sea water for each copepod is recommended, it has been found that survival is not affected by densities of up to 1 copepod/10 ml.

Introduction

The diatom Phaeodactylum tricornutum Bohlin has been used in numerous experiments on the physiology and biochemistry of diatoms since the publication of the first paper involving this organism by Allen & Nelson (1910). The taxonomic position of the organism has been dealt with by Lewin (1958), who also lists the papers which she considers to have involved the use of P. tricornutum. The present study reports the results obtained from a comparison of different isolates of this organism.

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.

A dense population of Polybius henslowi Leach was recorded at the surface of the sea 15 miles off the north coast of Spain. The depth of water at this point was 1740 m. Visual observations of the swimming behaviour show that Polybius tends to swim with the body facing diagonally and backwards against the current. The space between individuals appears to be maintained deliberately and was never less than 6 ft. during daylight. Measurements show that there are at least two sizegroups present. Females represent 40% of the total of 251 animals collected, and these were at approximately the same reproductive state with the ova maturing. The males are on average 2·3 mm longer than the females. No food was found in the stomach of any of the animals taken.

The subumbrella of the hydrozoan medusa Obelia consists of three layers of cells. The innermost layer is the endodermal lamella whose broad polygonal cells are in close contact with the middle layer of polygonal myocytes which have striated myofibrils running in two layers at right angles to one another in the same cell. These myofibrils extend beyond the myocytes as plasma membrane-enclosed prongs to make contact with the prongs of neighbouring cells in such a way that whole mounts give the impression that the slender myofibrils are continuous over the subumbrella. Cross-layered myocytes can be seen to be another means of decreasing the surface area of the subumbrella, a condition necessary for medusoid locomotion. Helically banded radial myofibrils are found in the outer layer.

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.

57Co-labelled vitamin B12 was used to study the kinetics of vitamin B12 limitation in Monochrysis lutheri in continuous and exponentially growing batch cultures and in washed cell suspensions.

Specific growth rate in the chemostats was found not to depend directly on medium substrate concentration but on the concentration within the cells (cell quota), obeying a hyperbolic equation of the form

The macrofauna, defined as infauna retained on a ½ mm sieve, was investigated on a flatfish nursery ground at less than 10 m depth in a Scottish westcoast sea loch during spring and late summer of 1965. The substratum consisted of well-sorted sand of 180–260 μ median diameter, and the infauna had a mean density of 755 individuals and biomass of 1·3 g dry weight/m2 on the beach and 3055 individuals and 3·7 g dry weight in the sublittoral. There was little overall change in the biomass during the period studied, increases in amphipods and some polychaetes being balanced by decreases in other polychaetes, and in Tellina for which no recruitment took place. The distribution of the fauna was studied in detail between high-water mark on the beach and a depth of 10 m below low-water springs. There were 62 species on the beach and 116 on the sublittoral sand. The number increased as the water deepened, the poorest zone being just below low-water mark. Most species showed a distinct zonation. The epifauna of the sand, which was dominated by juvenile stages of plaice and dabs, is briefly described

A photochemical reactor, using a medium power mercury arc lamp for oxidation of organic matter in sea water, is described. The decomposition of some known compounds in distilled water and in sea water, using a 380 W lamp, was followed. First order kinetics with rate constants in the range 0·2–4·0 h−1 were observed. All the nitrogen compounds tested, including urea and some of its derivatives, were oxidized quantitatively. Breakdown of phosphorus compounds was rapid, but polyphosphate esters yielded polyphosphate ion which was only slowly hydrolysed to reactive orthophosphate. If polyphosphate is to be determined, hydrolysis by heating with acid should follow the irradiation. Some samples of English Channel water contained 0·02-0–05 fig-axom P/1. as organic polyphosphate.

The earlier investigations (Raymont, Austin & Linford, 1964, 1966) on the brackish-water, semi-planktonic mysid, Neomysis integer (Leach), dealt with the total protein, lipid and carbohydrate fractions, together with chitin and ash. Results showed that a relatively high protein content (mean 71 % dry weight) was typical of Neomysis; the protein showed very little change throughout the year. Lipid was much lower and more variable (7–15%; mean 13 % dry weight), and carbohydrate was especially low (mean 2.5 % dry weight). Ash and chitin together amounted to some 14 % dry weight (Raymont et al., 1966).

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.

Campecopea hirsuta (Montagu) occurs in rock crevices, and among barnacles and the lichen Lichina in south-west Britain. It is particularly abundant on shores ex-posed to wave action, occurring most commonly at about M.T.L. and below on shallow slopes, and from M.T.L. to H.W.N. on steep slopes. Young Campecopea of about 1–5 mm long are released in late summer. Females attain a maximum length of 35 mm and males 4–0 mm, each having a life span of no more than 1½ years.

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.

Analyses of sea water collected during the years 1962–65 at International Hydrographic Station E. I are given here in the same form as in earlier reports. Temperature, salinity, nitrate, phosphate, and silicate were examined. Some values of suspended carbon and chlorophyll are also included.

Salinities were markedly higher in 1965 than in the previous 3 years. All 4 years showed a low value for maximum winter phosphate levels.

The distribution, abundance, and types of micro-organisms attached to littoral and sublittoral sand grains have been described. Micro-organisms are present in colonies, ranging from 5 to 150 cells per colony. Many colonies consist of one species. Some colonies are in or surrounded by staining material, others are on flat unstained surfaces. Colonies in staining material often occur in hollows. Large areas of surface between the colonies and staining material are completely bare. Evidence suggests that abrasion may stop micro-organisms colonizing flat or convex surfaces. On grains from the sediment surface, bacteria, blue-green algae (Cyanophyceae), and diatoms (Bacillariaceae) are common. The microbial flora may alter only slightly to depths of 15 cm below the sediment surface, or may change within a few mm. It is sparse towards high water, but differs little between lower littoral and sublittoral sands. The results are discussed in relation to substrate selection by marine invertebrates.

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.

Experiments have been made to elucidate the problem of hyperosmotic regulation in the mud-dwelling euryhaline amphipod, Corophium volutator. The animal produced urine hypo-osmotic to the blood when acclimatized to low salinities, and isosmotic urine at salinities above 20%. The restricted permeable areas of the cuticle have been localized by silver staining. Over a range of salinities from 1 to 35 % C. volutator was found to maintain Na+, K-−, Ca2+, Cl-−, more concentrated than the medium, and Mg2~ less concentrated. The importance of these mechanisms in assisting hyperosmotic regulation is discussed.

The Preliminary Check-list of British Marine Algae (Parke, 1953), with three subsequent lists of additions and corrections (Parke, 1956, 1957, 1959), was superseded by the Revised Check-list of British Marine Algae (Parke & Dixon, 1964). Since the publication of the latter, changes, both taxonomic and systematic, have been sufficiently numerous to warrant the present list incorporating additions, corrections and emendations.

The authors take full responsibility for all the changes from the 1964 Check-list. The responsibility for the preparation of the lists of species for each Class in the 1964 Check-list was as follows: (1) Cyanophyceae, H. T. Powell; (2) Rhodophyceae, P. S. Dixon; (3) Cryptophyceae, M. Parke; (4) Dinophyceae, D. Ballantine & M. Parke; (5) Haptophyceae, M. Parke; (6) Chrysophyceae, M. Parke; (7) Craspedophyceae, M. Parke; (8) Xanthophyceae, M. Parke; (9) Phaeophyceae, H. Bladder, G. Russell, P. S. Dixon & M. Parke; (10) Prasinophyceae, M. Parke; (11) Chlorophyceae, E. M. Burrows, P. S. Dixon & M. Parke.

The sequences of classes is as in the 1964 Check-list and there have been no changes in the geographical limits used therein (the coasts of Britain and Ireland or in adjacent waters, i.e. the sea area bounded by 47° N. and 63° N., 11° E. and 30° W.). Three classes (Bacillariophyceae, Rhaphidophyceae, Euglenophyceae) are still not represented and the authors would be grateful for records of marine species of these in order to facilitate their inclusion at some time in the future.

The compilers welcome any comments on the Revised Check-list (1964) or the present list.