bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecological and non-environmental constitutional resistance of the protoplasm of marine algae
Authors: Biebl Richard
Published: May 2009

Marine algae supply good examples of the difference between ‘ecological’ and ‘non-environmental constitutional’ resistance of the protoplasm of their cells to variations in the environment. The resistance to ecological factors such as diluted or concentrated sea water, to desiccation, or to light exposure is very similar among algae occupying the same habitat. On the basis of the degree of resistance shown, three ecological groups can be distinguished: (1) algae from the intertidal zone; (2) algae from the low-water level and tide-pools; and (3) sublittoral algae.

On the other hand, there is no similarity in the resistance to chemical substances (H3BO3, ZnSO4, MnSO4, VOSO4) of algae within a given ecological group. It is characteristic for a given species.
Studies on the parasites of Cardium edule L.: Cercaria fulbrighti n.sp., a Gymnophallus larva with a forked tail
Authors: Hutton Robert F.
Published: May 2009

A summary of the trematode parasites which have been recorded from the cockle is given.

A furcocercous, Gymnophallus larva, Cercaria fulbrighti n.sp., from the marine bivalve Cardium edule L., is described from Plymouth, England. The tail of this larva may degenerate completely while the cercaria is still within the sporocyst.

Simultaneous development of more than one species of cercaria has been recorded in four out of 420 specimens of C. edule L. Two double and two triple infections were found.

Available evidence suggests a phylogenetic relationship between the Gymnophallus group and certain of the Furcocercous cercariae.
Further experiments on biological differences between natural sea waters
Authors: Wilson Douglas P. , Armstrong F. A. J.
Published: May 2009

In one experiment sea water from the Firth of Clyde yielded better cultures of Echinus esculentus larvae than did sea waters from two positions in the English Channel.

From the Clyde water materials of unknown composition were extracted, using active carbon and acetone. The addition of these materials to both Clyde and Channel waters resulted in the death of the Echinus eggs during early cleavage. A similar extraction from Channel water had the same effect. The Clyde and Channel waters from which these materials had been extracted gave poor abnormal cultures, especially the Channel water in which most larvae died early. A few, however, survived, and later on some of these grew into almost normal plutei.
The boar fish, Capros aper (L.), as a possible biological indicator of water movement
Authors: Cooper L. H. N.
Published: May 2009

Notable catches of boar fish (Capros aper) were taken near the Eddystone on 30 October and in early November 1951. From what is known of the distribution of boar fish and from the hypothesis on the genesis of “submarine eagres” in canyons on the continental slope, a further hypothesis has been derived to explain this occurrence. It is suggested that strong west to south-westerly winds on 24 September created conditions to produce a submarine eagre the following day, and that this swept a shoal of boar fish from the yellow-coral encrusted walls of a submarine canyon in the southern edge of the Celtic Sea on to the continental shelf. Thence during quiet weather the shoal was carried by currents to the neighbourhood of the Eddystone at about 6 miles a day. Further deductions which lead to means of checking the present hypotheses have been drawn.
Forty Years of Changes in Species Composition and Population Density of Barnacles on a Rocky Shore Near Plymouth
Authors: Southward A. J.
Published: May 2009

The abundance of the common intertidal barnacles, Chthamalus montagui, Chthamalus stellatus, Semibalanus balanoides and Elminius modestus has been monitored since 1951 at a site near Cellar Beach, River Yealm, south Devon. Counts are made at 12 levels on a transect between high tide and low tide. The two chthamalids are of warm-water distribution while S. balanoides is a boreo-arctic species; changes in the abundance of these species are linked to environmental temperature. Maximum fluctuations occur in the lowermost third of the intertidal zone. The proportion of Chthamalus adults is correlated with annual mean inshore sea temperature two years earlier, while the proportion of S. balanoides adults is negatively so correlated. This relationship accounts for over 40% of the variance. A smaller part of the variance (<20%) is explained by intensity of larval settlement, also related to climate. The fourth barnacle, E. modestus, is an Australasian immigrant that arrived in England during World War II and reached south Devon in 1948. It increased during the 1950s on the transect but has since stabilized at a low level of abundance that shows large interannual variations not directly related to temperature. Between 1951 and 1975, coinciding with a secular decline in sea temperature, there was a long-term trend towards reduction of Chthamalus and increase in S. balanoides; this trend has reversed since. Removal of the long-term trend reveals a short-term fluctuation of approximately 10-y frequency that correlates with a cycle in sea temperature two years earlier. These cycles are close to the 10–11 y solar (sunspot) cycle between 1951 and 1975.
Seasonal Changes in Epipelic Diatoms Along an Intertidal Shore, Berrow Flats, Somerset
Authors: Oppenheim Deborah R.
Published: May 2009

Seasonal changes in the assemblage structure of dominant epipelic diatoms were studied along a transect crossing a salt marsh, sandflat, and mudflat of an estuarine intertidal shore at Berrow Flats, Somerset, UK. Seasonal changes in cell numbers displayed different patterns in the salt marsh and sandflat/mudflat. At salt marsh sites highest numbers of individuals were recorded in summer followed by a smaller autumn growth, while in the sandflat lower numbers showed no seasonal pattern. Repeated annual patterns in the succession of taxa were not observed as environmental conditions changed at the study site with time. Measurements of salinity, pH, interstitial water content, air and soil temperature were taken together with the diatom samples. A canonical correspondence analysis was employed to relate seasonal changes in assemblage structure to measured environmental variables. Total percentage variation in the first four axes of the species/site-environmental biplots ranged between 54 and 66°. In winter, sites and species separated most significantly along gradients of salinity and levels of organic matter. In spring and autumn, interstitial water content became a more significant environmental variable. By summer steep gradients in pH, levels of organic matter, and hypersaline conditions separated sites and assemblages into more discrete groups when compared to the more even spread of points in the other seasons. The results indicate that different combinations of environmental variables influence diatom assemblage structure seasonally.
A Reassessment of the Genus Strombidinopsis (Ciliophora, Choreotrichida) with Descriptions of Four New Planktonic Species and Remarks in its Taxonomy and Phylogeny
Authors: Lynn D. H. , Montagnes D. J. S. , Dale T. , Gilron G. L. , Strom S. L.
Published: May 2009

Strombidinopsis species were collected from theGulf of Alaska, Gulf of Mexico, Caribbean Sea, Gulf of Maine, and Barents Sea. Six strains were conservatively placed in six species: Strombidinopsis chilorhax sp. nov.; Strombidinopsis batos sp. nov.; Strombidinopsis sphaira sp. nov.;Strombidinopsis cercionis sp. nov.;Strombidinopsis acuminatum Fauré-Fremiet, 1924; and Strombidinopsis spiniferum (Leegaard, 1915) comb. nov. Based on the characters of these species, the diagnosis of the genus Strombidinopsis was revised.
Two New Mesopelagic Appendicularians: Inopinata Inflata Gen. Nov., Sp. Nov., Mesopelagica Caudaornata Gen. Nov., Sp. Nov.
Authors: Fenaux R. , Youngbluth M. J.
Published: May 2009

Two new Appendicularians: Inopinata inflata gen. nov., sp. nov. and Mesopelagicn caudaornata gen. nov., sp. nov., from the family Oikopleuridae (Lohmann 1915), subfamily Oikopleurinae (Lohmann 1896a), are described from specimens collected at mesopelagic depths (660–840 m) in Bahamian waters by the ‘Johnson-Sea-Link’ manned submersibles.
Effects on Dietary Lipids of the Marine Bivalve Scrobicularia Plana Feeding in Different Modes
Authors: Bradshaw Stuart A. , O'Hara Sean C.M. , Corner Eric D. S. , Eglinton Geoffrey
Published: May 2009

Changes in dietary lipids were investigated in laboratory feeding experiments simulating herbivorous and coprophagous modes of feeding in the bivalve mollusc Scrobicularia plana (da Costa). The dinoflagellate Scrippsiella trochoidea (Stein) was used as the food in herbivory experiments while faeces from the crustaceanNeomysis integer (Leach) feeding on Scrippsiella were used as the food in coprophagy experiments. Changes in dietary total fatty acids, sterols and fatty alcohols were characterised by analyses of the food, faeces andanimal tissues using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).

There is a net decrease in the total lipid of the digested material during both herbivory and coprophagy. However, while fatty acids are assimilated, sterols are contributed to the faeces, leading to a decrease in the fatty acid:sterol (FAST) ratio of the digested material. Coprophagy decreases the ratio still further, such that faeces have a FAST ratio of <1

Scrobicularia preferentially assimilates dietary polyunsaturated fatty acids (PUFAs). Reworking of sedimentary material (as in coprophagy) will lead to PUFA-deficient sedimentary fatty acid distributions. Both herbivory and coprophagy lead to relative increases in 'bacterial' odd carbon-number normal and branched fatty acids in the digested material, though not the 'bacterial' marker 18:1 Benthic molluscan feeding, particularly coprophagy, contributes partly to the 'bacterial' fatty acid content of the sediments.

Scrobicularia contributes its own sterols to the faeces, especially cholesterol. Such contributions aredependent on the dietary sterols present. With a cholesterol-poor diet (herbivory), A5 4–desmethyl sterols are contributed to the faeces and dietary A8(14) sterols decrease, suggesting a A8(14) U021e2; A5 conversion may occur. With a cholesterol-rich diet (coprophagy), the A5 sterol is taken up from the diet.
Size Fluctuation in The Eggs and Newly Hatched Larvae of Captive Turbot(Scophthalmus Maximus)
Authors: Mcevoy Lesley Ann , Mcevoy John
Published: May 2009

The aims of this study were to ascertain if individual turbot females show a seasonal decline in their egg-size when kept in conditions of constant temperature, and to relate turbot egg-size to the length and yolk-sac index of the emergent larva. Each female showed a significant seasonal egg-size decline and there was a positive correlation between egg-size and the length and yolk-sac index of the subsequent larva. However, larval length was not related to yolk-sac index, nor was the ratio of yolk-sac index: larval length related to egg-size. The maximum mean egg-size tended to increase with the female's weight and length. The implications of these findings are discussed in terms of the general ecology of turbot and its culture.
Colour Polymorphism in Relation to Spatial Distribution in Some Intertidal Isopods in Northern Spain
Authors: Arrontes Julio
Published: May 2009

The hypothesis that the level of chromatic polymorphism in intertidal isopods is related to their distribution and seasonal fluctuations in abundance was examined in northern Spain. Four species were used,Dynamene bidentata, Dynamene magnitorata, Cymodoce truncataandCymodoce emarginata. Only forDynamenespecies were results consistent with initial hypothesis. The most common colour morph inDynamene bidentatawasuniformiswhich is the most flexible phenotype, allowing effective concealment in most of the environments where the species occurs.Dynamene bidentatais the most abundant species of isopod in northern Spain, where it is abundant along the shore and throughout the year. Distribution of D.magnitorata, Cymodoce truncataand C.emarginatais restricted to macroalgal assemblages at low tidal levels. Seasonality is also important in D.magnitorataand C.truncata. The number of colour morphs and phenotypic diversity was larger in D.magnitoratathan inD. bidentata. Only one colour morph was found in C.truncataand four in C.emarginata.
Some Aspects of the Specific Habitat Requirements of Ophelia Bicornis (Polychaeta)
Authors: Harris Tegwyn
Published: May 2009

The discrete habitat requirements of Ophelia bicornis from the Exe estuary are reported in relation to: the influence of tidal activity; the nature of the sandy substratum; the associated meiofauna; the interstitial bacteria; the interstitial water, organic matter and calcareous material; and the interstitial and sand-adsorbed free amino acids. The interrelationships of these features as potential limiting factors in the highly specific littoral distribution of O. bicornis is speculated upon.
The Age Structure and Growth Dynamics of Young-Of-The-Year Bass, Dicentrarchus Labrax, Populations
Authors: Jennings S. , Lancaster J. E. , Ryland J. S. , Shackley S. E.
Published: May 2009

Back-calculated egg fertilization (spawned) dates and growth rates for young-of-the-year bass, Dicentrarchus labrax (L), captured from Loughor Estuary, Oxwich Bay and Ogmore Estuary, south Wales, UK, during 1988 and 1989 were compared. Spawned date frequency distributions indicated that the bass spawning season began in late February and continued until early June in 1988 and early July in 1989.

There were no significant differences in the frequency distributions of back-calculated spawned dates for the bass populations, between either sites or years, which suggested that any variations in growth rates were attributable to characteristics of their respective environments. Growth rates were determined for bass cohorts resulting from early, midor late-season spawnings at Oxwich and Loughor in 1988 and Oxwich, Loughor and Ogmore in 1989. There were only slight intra-annual differences between the mean growth rates of bass cohorts at the same site, suggesting that bass from early cohorts would be larger at any given time of year. In 1989, growth was considerably faster at Oxwich and Loughor than at Ogmore, where food supply was considered limiting. However, between-site variations in growth rate were small in comparison with inter-annual differences. The faster growth rates observed at Loughor and Oxwich in 1989 were attributed to higher water temperatures.

Relationships between growth rate and subsequent survival of young-of-the-year bass, and the relative importance of estuaries as nursery habitats for juvenile bass, are discussed.
The Uptake and Accumulation of Zinc and Copper From Solution by two Species of Talitrid Amphipods (Crustacea)
Authors: Weeks J. M. , Rainbow P. S.
Published: May 2009

The exposure of two species of talitrid amphipods(Orchestia gammarellusandOrchestia mediterranea)to a range of zinc and copper concentrations in solution has enabled the categorization of the mode of metal accumulation adopted by these supralittoral amphipods. Both species showed net accumulation of dissolved zinc and copper at all experimental exposures between 20 and 1000 μig Zng 1 and 13 and 1000 μg Cu 1 in artificial sea-water. Studies using Zn have shown that the zinc uptake rates of both species (0·430 μg Zn g d, SE 0·032 and 0·408 µg Zn g d, SE 0·073 forO. gammarellusandO. mediterranearespectively at 10°C in 31·6 μg Zn 1) are not significantly different, and are low in comparison with other crustaceans. Laboratory results are related to field conditions, and it is concluded that Firth of ClydeO. gammarellusare more dependent upon a food source in order to meet both their copper and zinc requirements than areO. mediterraneawhich are able to obtain sufficient metabolic copper from solution. The use of talitrid amphipods in zinc and copper biomonitoring programmes is also discussed.
The American Oyster Drill, Urosalpinx Cinerea (Gastropoda): Evidence Of Decline in an Imposex-Affected Population (R. Blackwater, Essex)
Authors: Gibbs P. E. , Spencer B. E. , Pascoe P. L.
Published: May 2009

The American oyster drill, Urosalpinx cinerea introduced to UK waters around the turn of the century, flourished in the Essex oyster grounds until the 1970s. Recent observations, 1987–1990, made in Goldhanger Creek, River Blackwater, indicate that the population level has been reduced to the point of scarcity and that those individuals remaining are old. All females examined exhibited imposex. In most, this masculinizing syndrome was developed to an advanced state that involved oviducal malformation; copulation and egg capsule formation are thought to have been inhibited and hence such affected females were sterile. Other, probably very old, females appeared infertile because of senility. No viable spawn was observed during the four summers of 1987 – 1990.
The Logic of Ecological Experiments: A Case History From Studies of the Distribution of Macro-Algae on Rocky Intertidal Shores
Authors: Underwood A. J.
Published: May 2009

The various steps involved in experimental investigations of the causes of observed ecological patterns are examined. A sequence of different steps (observation, model, hypothesis, null hypothesis, test) is identifiable. The logical necessity for distinguishing and evaluating each of these steps is discussed. The potential usefulness of explicit recognition of the logical relationships between the various parts of the procedure is evaluated by reference to experimental studies to determine the causes of boundaries of vertical distribution of macro-algae in rocky intertidal habitats. Pitfalls of experimental procedures can sometimes be recognized as failures in the logical progress from one part to the next in the sequence of steps necessary in any study. Particularly important is the early recognition of the existence of many, potentially conflicting, but sometimes interactive, models to account for any observed pattern. Greater attention to the relation-ships between the components of the logical structure of an experimental study might aid in reduction of errors in the design, analysis and interpretation of ecological experimental data.
Seasonal Variation in Pilayella Littoralis (Phaeophyceae) and its Consequences as a Food Source for the Amphipod, Gammarus Lawrencianus, in the Intertidal of Newfoundland
Authors: Steele D. H. , Whittick A.
Published: May 2009

The brown alga Pilayella littoralis is common and widely distributed in the North Atlantic. In insular Newfoundland it is found year-round in the subtidal, but shows a distinct periodicity in the intertidal where it is a summer annual. Rapid growth begins in May and a maximum biomass is achieved in the summer with plants disappearing by October. Besides seasonal changes in abundance, seasonal changes in reproductive behaviour and calorific values of this alga also occur.

Pilayella littoralis is the most abundant consumable alga available to intertidal amphipods in Newfoundland. Newly hatched Gammarus lawrencianus grew faster and matured at a younger age on a diet of summer P. littoralis than on plants collected in the spring. Size at maturity and reproductive output (size of eggs, number of eggs) of maturing females did not vary with the time of collection of Pilayella.
Interactions Between the Amphipod Corophium Volutator and Macroalgal Mats on Estuarine Mudflats
Authors: Raffaelli D. , Limia J. , Hull S. , Pont S.
Published: May 2009

One of the most obvious effects of eutrophication in sheltered coastal areas and estuaries is enhanced growth of opportunistic macroalgae, which may form extensive mats over intertidal mudflats during the spring and summer. In the Ythan estuary, densities of the amphipod Corophium volutator (Pallas) in the sediment underlying weed mats were significantly lower than those in weed-free sediments, and are dominated by species characteristic of organically enriched, low oxygen environments such as Capitella capitata. Long-term data sets on Corophium abundance in the Ythan suggest that this species has declined dramatically throughout those parts of the estuary affected by weed mats.
The Habits of the Angler-fish, Lophius piscatorius L., in the Plymouth Aquarium
Authors: Wilson Douglas P.
Published: May 2009

1. Young angler-fishes have been kept alive and in health for periods varying from a few weeks to eleven months. They were sometimes hand-fed on dead fishes and sometimes allowed to catch living prey. They grew at an average rate of about eight and a half inches per annum. All had strongly marked individual characters.

2. With pelvic and pectoral fins a slight hollow is made in the sand into which the angler settles itself. Its upper surface is now flush with the ground, and the colour and colour mottlings are closely matched to the surroundings. The bordering tags of skin break up the outline.

3. Breathing movements occur at relatively long intervals. The expiratory currents are discharged in the axils between the pectoral fins and the trunk, and are deflected vertically upwards.
The Air Turbine Ultracentrifuge, together with some Results upon Ultracentrifuging the Eggs of Fucus serratus
Authors: Beams H. W.
Published: May 2009

1. An air turbine ultracentrifuge suitable for biological work and capable of developing a centrifugal force from 10,000 to 500,000 times gravity has been described. Advantages of the ultracentrifuge are: (1) The temperature does not vary in the centrifuge chamber over 2 or 3 degrees from that of the atmosphere; this is not sufficient to be an important factor in general biological work. (2) The cost of constructing the apparatus is very low in comparison with that of other high speed centrifuges.

2. A modification of the air turbine ultracentrifuge in which the turbine rotor drives a second rotor, in this case the centrifuge rotor which spins in a vacuum, has been described. Here the centrifuge chamber is thermally insulated which is an important item in preventing troublesome convection currents from arising in the centrifuged material where such special problems as the rate of molecular sedimentation are being observed. Forces in excess of one million times gravity can easily be obtained by such an apparatus.
The Fauna of Certain Estuaries in West England and South Wales, with Special Reference to theTanaidacea, IsopodaandAmphipoda
Authors: Crawford G. I.
Published: May 2009

Duringthe summer of 1935 Captain Nicholson of Saltash kindly put his motor-boat at my disposal and took me for seven full-day collecting trips on the estuaries of the Tamar and its confluents, the Tavy and Lynher. I also made some collections from land in the estuaries of the Plym and Exe (S. Devon), Taw (N. Devon), Camel (N. Cornwall), and Towy (S. Wales).

All collecting was done intertidally or in shallow water and was practically confined to the brackish-water reaches. No gear was used except a hand-net of stramin, and a zinc sieve of 1-mm. mesh. More attention was paid to the Crustacean orders Tanaidacea, Isopoda, and Amphipoda than to the rest of the fauna, observations on which were only occasionally made.
Larval and Post-larval Lima from Plymouth
Authors: Lebour Marie V.
Published: May 2009

Two species of Lima are known from Plymouth: Lima hians (Gmelin), the commonest species, inhabiting small patches of stones with muddy gravel at extreme low-tide mark on the north side of the Breakwater, where many individuals may be found together, and Lima loscombi Sowerby, found on the coarse grounds west of the Eddystone, Rame-Eddystone Grounds, Mewstone Grounds, Stoke Point Grounds and southwest of the Eddystone (see Marine Biological Association, Plymouth Marine Fauna, 1931). The latter is a much smaller species than the former, not so highly coloured, and much rarer. Although it is often difficult to obtain Lima hians, as it is only accessible at very low tides, it occurs in numbers in the locality cited.
On a Remarkable Process of Bud Formation in a Gymnoblastic Hydroid (Heterostephanus sp.)
Authors: Rees W. J
Published: May 2009

The process of asexual reproduction, described below, is, as far as the writer is aware, unique among hydroids. In all known species of hydroids in which an asexual bud formation has been described (e.g. in Hydra), the mouth and oral tentacles develop at the free end of the bud and the proximal or fixed end becomes the base. The sequence of development of medusa buds is essentially similar. This method applies also to budding in other Coelenterates. In the present instance the bud instead of growing out “head first,” came off “tail first,” came off “tail first” –the proximal end developing mouth and oral tentacles and the free end becoming the stalk. I can find no recoid of such a method having been described before.
Alternation of generations in a coccolithophorid, Cricosphaera carterae (Braarud & Fagerl.) Braarud
Authors: Rayns D. G.
Published: May 2009

Material of Cricosphaera carterae was examined cytologically with the acetocarmine technique. Nuclear division is similar to that found in higher plants. Investigations showed there to be a chromosomal alternation of generations, which corresponds to the morphological alternation. The motile phase is diploid, 2n = 42 ± 2, and the non-motile phase is haploid, n = 21 ± 1.
A new bottom-water sampler for ecologists
Authors: Murray J. W.
Published: May 2009

In ecological studies of benthonic organisms it is advisable to sample the water immediately above the sediment-water interface rather than centimetres or metres above the bottom. The standard oceanographic water samplers cannot be relied upon to sample at the required level so a new instrument was designed. The instrument here described is a strengthened and simplified version of that described for use in shallow waters (up to 4 m) by Murray (1963). It has been successfully used in waters of up to 60 m deep but should withstand depths of up to 180 m.
The class Kinorhyncha (Echinoderida) in British waters
Authors: McIntyre A. D.
Published: May 2009

Records are given of Kinorhyncha from muds at 101–140 m depth off the Scottish east and west coasts. All three suborders of Kinorhyncha are represented, and one new species and two new larvae are described.
Carbohydrate as a measure of phytoplankton
Authors: Marshall S. M. , Orr A. P.
Published: May 2009

Counting the numbers of phytoplankton organisms in water samples is time-consuming. A knowledge of the kind of organisms present and their relative numbers is essential, but it is useful to have in addition a measure of the quantity of organic substance present. A number of methods have been suggested for measuring the standing crop of phytoplankton and these have been summarized recently by Strickland (1960).
The ecology, distribution and taxonomy of the centipedes found on the shore in the Plymouth area
Authors: Lewis J. G. E.
Published: May 2009

Six species of geophilomorph centipede are reported from the littoral zone in the Plymouth area, and in two cases, where they differ from previous descriptions, the significance of these differences is discussed. It is suggested that the various British and French populations of Geophilus algarum and Geophilus fucorum may be subspecies of one polytypic species.

It is shown that Strigamia maritima and Hydroschendyla submarina differ in the way in which they have adapted to life on the shore. The former lays permeable eggs and migrates out of the littoral zone to lay them and to moult, the latter lays impermeable eggs and moults in the intertidal zone. Information on the prey of S. maritima at Plymouth is given.

The variations between some populations of littoral centipedes is discussed and possible reasons for the high density of populations of S. maritima and H. submarina are given.
Phosphorus and iron in Sagitta setosa and Sagitta elegans
Authors: Harrison R. J.
Published: May 2009

The amount of iron and phosphorus in Sagitta setosa and S. elegans has been estimated. As the winter population decreased in numbers the iron content per animal also decreased, rising again in what may have been the next brood.
The biology of Littorina littorea. Part II. Zonation in relation to other gastropods on stony and muddy shores
Authors: Moore Hilary B.
Published: May 2009

The survey, the results of which are described in this paper, was primarily intended to investigate the zonation of Littorina littorea, but notes have also been included of the zonation of such other gastropod species as occurred with it. The material was collected from the following localities: Torpoint. 2. ×. 36. Just west of the ballast dock at Torpoint, Cornwall. The shore consists of stones, many of them bedded in mud, and thickly overgrown with fucoids. There is little wave-action, but at times a considerable drop in salinity (Hartley & Spooner, 1938; Mime, 1938).
A cubical photometer for studying the angular distribution of submarine daylight
Authors: Atkins W. R. G. , Poole H.H.
Published: May 2009

Preliminary observations have been made in the English Channel off Plymouth on the average obliquity of illumination under water, and on the relative intensity of light reflected upwards at various depths, the readings being made with a cubical photometer containing six “Electrocell” selenium rectifier cells mounted behind opal glasses and Jena VG 9 (green) filters. The cells measured the light of wave-lengths about 480–580 mμ falling on upward-and on downward-turned horizontal surfaces, and on four vertical surfaces i n rectangular azimuths.

The average angle with the vertical or of obliquity was from 36 to 40°, and no significant difference could be detected between that for smooth sea and overcast sky, and that for rough sea and either high or low sun. Figures for smooth sea and sunlight are more difficult to obtain, as in the absence of drift due to wind the photometer may rotate.

No decrease in average obliquity with depth was found, in some cases there was evidence of a slight increase. This is in accordance with our previous results, and accords well with the constancy of extinction coefficient so often found throughout a series. It is not, however, in agreement with the careful work of Johnson & Liljequist, so further determinations would seem to be desirable.

The percentage of the light which was scattered back so as to fall on a downward-turned surface varied from 5.5 for comparatively opaque water (extinction coefficient 0.20) inside Plymouth breakwater, to 2.1 for very clear water (extinction coefficient 0.076) some miles off at sea. The presence or absence of sunlight had little effect, values close to 3.0 being obtained with and without sun for water having a coefficient close to 0.110.
Fluctuations in oyster production in the Fal Estuary
Authors: Orton J. H.
Published: May 2009

A survey of the Fal Estuary Beds in February 1939 gave evidence that the stocks of oysters were only slightly better than in the slump period of 1926.

The failure of the beds to show the recovery expected in recent years is attributed largely to the absence of sufficient clean culch on the banks.

It is suggested that means be taken to scatter clean culch over the banks in June yearly to prevent further decline of the beds and assist in their more rapid recovery to a flourishing condition.

The American slipper limpet, Crepidula fornicate, was not found and appears to be unknown on the beds.
The rearing of oyster larvae on an algal diet
Authors: Bruce J. R. , Knight Margery , Parke Mary W.
Published: May 2009

The work described in this paper is a contribution to the general problems of rearing the larvae, and growing the spat of the European flat oyster, Ostrea edulis L.

The specific aspect of the problem dealt with in detail is the place taken by minute motile organisms (naked dinoflagellates and other unicellular algae) in the food requirements of the developing veliger larvae.

Six such flagellate organisms, ranging in size from 1·5 to 7 μ in diameter, have been isolated from sea water, and are maintained in pure culture, under conditions described. Pending specific identification, these are denoted by letter-labels only. These organisms have been used, over a period of years, in feeding experiments with oyster larvae.
The fecundity of Ostrea edulis
Authors: Cole H. A.
Published: May 2009

It is shown that the average number of embryos produced by a gravid oyster is approximately doubled each year until the oyster is 4 years old, when it may be regarded as adult. Estimates have been made of the quantities of embryos produced by one 1-year-old, eleven 2-year-old, fourteen 3-year-old and twenty-two adult oysters; the mean values for these year-classes are 91,600, 218,100, 462,600 and 902,900 respectively.

Since it is probable that the proportion of a population of oysters which matures in the female phase increases progressively up to the age of 4 years, it follows that adult oysters are for this reason superior to 2- or 3-year-old oysters as breeding stock, quite apart from the increased number of embryos produced by each oyster.
Metric variations in populations ofCarcinus moenas
Authors: Williams G. , Needham A. E.
Published: May 2009

1. Measurements ofCarcinus, comparable to those taken by Weldon at Plymouth 40 years ago, have been made on material from three Irish localities, the observations in each area extending over three years. The three localities afford different environments, one having no silt, one a moderate amount and the other much silt.

2. The results support the view that the change in the ratio frontal width/ carapace length with increase in body size is due to differential growth in the individual and is not caused, as Weldon supposed, by the continuous removal through natural selection of those crabs with a relatively wide frontal aperture. Measurement on the growth of individuals confirms this view.

3. A striking fact which emerged from Weldon's work was that the ratio mentioned above showed a successive diminution in each of the three years covered by the observations. A precisely similar diminution has been found at each of the Irish localities, and it is shown that the annual differences are mathematically significant.

4. The results disprove Weldon's hypothesis that the change in the ratio is correlated with the slow accumulation of silt in Plymouth Sound. The Irish locality with most silt has the widest frontal aperture and the intermediate locality the narrowest. It is also shown that the yearly trend towards a lower value for the ratio cannot be continuous, for the rate of change is too rapid to be maintained indefinitely, and the values obtained in the Irish localities overlap those at Plymouth 40 years earlier. Possible explanations of the changes are discussed.

5. The differences between populations from the three localities in any year are much less marked than the annual differences at one locality, and are not generally significant. Though small, however, they do show a consistent sequence among the three localities (but not corresponding to the order for siltiness).
The male of the amphipod Haustorius arenarius Slabber
Authors: Watkin Emrys
Published: May 2009

The male of Haustorius arenarius is identical with the female in all external morphological characters apart from the absence of brood lamellae. The females develop brood lamellae at 5 mm. total length, eggs appear in the brood pouch at 11 mm., and they may reach a length of 14 mm. The largest male obtained measured 10 mm.
On the life history and developmental stages of the medusaPodocoryne borealis
Authors: Rees W. J.
Published: May 2009

It has been shown in a recent paper by Russell (1940) that in addition toPodocoryne corneaM. Sars, 1846, and the so-calledP. areolata, two otherPodocorynemedusae, viz.P. hartlaubiNeppi & Stiasny, 1913, andP. minima(Trinci), also occur in the plankton in British waters. The identity of both hydroid and medusa of the EuropeanP. corneais well established arid the medusa has never been known to mature with more than 8 tentacles (Kramp, 1927; Russell, 1940).P. minimais a small medusa with only 4 tentacles and need not be considered further in this paper.
Osmoregulation in some palaemonid prawns
Authors: Kesava Panikkar N.
Published: May 2009

1. The brackish-water prawnPalaemonetes variansand the marine prawnsLeander serratusandL. squillaare hypotonic in normal sea water, the blood of these species showing osmotic pressures equivalent to 2·3, 2·8 and 2·6 % NaCl respectively, in an external medium of 3·5 % NaCl.

2.Palaemonetes variansis isotonic in water of about 2·0 % NaCl and the species is practically homoiosmotic, the difference in its osmotic pressure over a range of 5·0 % NaCl in the external medium being only 0·8–1·0 %. The species has a very wide range of tolerance from water that is nearly fresh to concentrated sea water equivalent to 5·2 % NaCl.

3.Leander serratusis much less homoiosmotic thanPalaemonetes, and has a limited tolerance to dilution and concentration of the environment. Homoiosmoticity is maintained up to a dilution of 2·5 % in the external medium when isotonicity is reached; but in lower dilutions there is a steady decline in osmotic pressure and the regulatory mechanism evidently breaks down.

4. The osmotic behaviour ofLeander squillais very similar to that ofL. serratus, but the homoiosmotic behaviour is more marked and it has greater tolerance to dilution of the environment.

5. WhenLeanderandPalaemonetesare transferred to very dilute sea water, the internal osmotic pressure falls gradually for about 14–24 hr., varying according to the size of the individual. After the lowest value has been registered there is a slight rise, and a steady state is thereafter maintained.

6. Studies on the changes of weight of prawns when transferred to diluted media indicate that the integument (gills) is permeable to water and that, at least inLeander serratus, the amount of water entering is mainly responsible for the dilution of the blood. There is a similar fall in weight when prawns are transferred to concentrated media, due to loss of water.
A wire-angle indicator for use when towing plankton nets
Authors: Moore Hilary B.
Published: May 2009

The old type of wire-angle indicator, which consisted of a pendulum swinging across an arc of a circle graduated in degrees, and which had to be applied by hand to the wire, was clumsy to use, especially in bad weather, and when the wire led out over the stern of the ship. It needed someone to attend to it, which often resulted in the wire angle not being checked more than once every five or ten minutes when the crew were busy. This instrument was therefore designed to remain in place throughout the tow, and to give a large dial reading which could be easily seen from a distance. On the research ketch Culver there is an engine throttle control mounted close to the wheel, and all the man there has to do is to adjust the engine speed so that the large indicator in the instrument remains on the red line. In practice it was found that the wire angle rarely varied more than about ±2°, except in very bad weather, and so the depth of the nets could be regulated very closely. The instrument is oil damped, so that the pitching of the ship and the vibration of the wire during hauling do not affect it. It has been used for about two years on the Culver at Bermuda; it has needed no attention in that time, and, which is a good point, the crew like using it.
Osmotic regulation in the embryo of the herring (Clupea harengus)
Authors: Holliday F. G. T. , Jones M. Pattie
Published: May 2009

Just before spawning the semen of the herring is isosmotic with the parent blood, the eggs are hyposmotic. Immediately the eggs are placed in sea water of salinities 5, 17·5, 35 and 50 %0there is a change in the freezing-point of the yolk indicating that it has approached close to being isosmotic with the water. Changes in the freezing-point of the yolk during development indicate that the overgrowing embryo gradually regulates the osmotic concentration of the yolk, although full regulation is not achieved until after the closing of the blastopore. After this point there is no significant change in the freezing-point of the yolk or body fluids. Regulation is most probably brought about by the activity of the cells of the ectoderm.
The fat/water relationship in North Sea herring (Clupea harengus), and its possible significance
Authors: Iles T. D. , Wood R. J.
Published: May 2009

Data from nearly 900 individual herring sampled in the North Shields, Whitby and East Anglian fisheries during the period 1956–60 demonstrate a linear relationship between the percentage fat and the percentage water contents for whole herring minus gonads and gut content, and the fat/water line derived from the data is described.
The relationship between cirral activity and oxygen uptake inBalanus balanoides
Authors: Newell R. C. , Northcroft H. R.
Published: May 2009

The rate of cirral beat ofBalanus balanoidesis related to the logarithm of the body weight as an exponential function. In any one animal, there is little effect of temperature on cirral activity between 7·5° and 10° C. Between 10° and 20° C, however, there is a rapid increase in cirral beat with temperature followed by a fall at temperatures above 20° C.

Balanus balanoidesexhibits a fast, medium and zero rate of oxygen consumption. These rates of oxygen consumption correspond with (a) normal cirral beating, (b) ‘testing’ activity with no cirral movement, and (c) with the closure of the mantle cavity. Both of the possible levels of oxygen uptake are related to the logarithm of the body weight in a logarithmic fashion over the temperature range 7·5°–22·5° C. Temperature affects the two rates of oxygen consumption differently. In the slower rate (rate B) there is an increase in the rate of oxygen consumption between 7·5° and 14° C but there is no significant increase in the rate of oxygen consumption between 14° and 22·5 C°.
Migration of chorioidal tapetal pigment in the spur dog Squaluls acanthias
Authors: Nicol J. A. C.
Published: May 2009

This research has been concerned with the movement of pigment in the occlusible tapetum lucidum of the spur dog Squalus acanthias. The pigment expands and covers the reflecting plates of the tapetum in light, and retreats and uncovers the plates in darkness. Movement of pigment in one eye occurs independently of that in the other. Normal movement of pigment is not affected by cutting the optic nerves and oculomotor nerves, by sectioning the cord immediately behind the medulla, nor by excising the pituitary and pineal glands. It is concluded that the process is not under nervous or hormonal control. It occurs normally in excised opened eyes that are kept in oxygenated Ringer solution, but not under partial or fully anoxic conditions. The pigment cells of the chorioid seem to be behaving as independent effectors, sensitive to light. The pigment expands in tapeta freed of retina, in light or darkness. No explanation is yet available for the latter anomalous result. Measurements were made of the reflectivity of isolated tapeta, and curves are presented showing the progressive decrease of reflectivity accompanying expansion of pigment, and changes in the colour composition of the reflected light.
The Hydroid and the medusaNeoturris pileata
Authors: Edwards C.
Published: May 2009

The hitherto unknown hydroid of the anthomedusaNeoturris pileatahas been found abundantly in the Clyde Sea Area, and medusae from it have been reared. The hydroid and the stages of development of the medusa are described and figured. The medusa is commonly present in the plankton in this area.
The American whelk tingle, Urosalpinx cinerea (Say), on British oyster beds
Authors: Cole H. A.
Published: May 2009

The American whelk tingle, Urosalpinx cinerea (Say), a gastropod enemy of oysters, has been introduced to Britain with American oysters and is now established in the rivers Blackwater, Colne, Crouch and Roach in Essex and on the Kentish Flats off Whitstable. Evidence available concerning the migratory powers of Urosalpinx is conflicting, but it is probable that migration is of local significance only in the spread of this pest. To infest new areas tingles or their spawn must be transported by human or other agency, for Urosalpinx has no free-swimming larval stage, the eggs being deposited in capsules from which fully formed young tingles emerge.

Females of Urosalpinx grow more quickly than males and reach a larger size. In males the annual increase in shell height never exceeds 0·2 cm. after the first 3 years, and is generally rather less. In females an annual increment of 0·2 cm., or slightly more, is general up to the age of about 7 years, after which it gradually falls. Males and females of the same age differ in height by about 0·25 cm. Growth marks are frequently to be seen on the shell and are of value in assessing growth rates. In both sexes a maximum age of 13–14 years may be reached. Urosalpinx reaches a much greater average size in Britain than in its natural habitat on the Atlantic coast of the U.S.A.

Females may deposit some spawn during the first 2 years of life, but the amount is insignificant in relation to the production of older tingles. Spawning begins when the water temperature in its seasonal rise reaches 12° C. Adult females may deposit an average of 25 egg capsules at a single laying, but it is possible that further capsules are deposited later in the season. The bulk of the spawn is deposited in May and June on British beds, but a few freshly laid capsules may sometimes be found in August and September. The average period of incubation is about eight weeks. Young tingles usually begin to emerge early in July. The average number of young emerging from each capsule is 11–74. Urosalpinx appears to be more prolific on British oyster beds than in America.
The distribution of Arachnactis albida M. Sars in the Celtic Sea
Authors: Corbin P. G. , Panikkar N. Kesava
Published: May 2009

The distribution of Arachnactis albida in the Celtic Sea in 1937–9 is described. The species appears, to have a definite centre of distribution in the neighbourhood of lat. 50° N., long. 10° W. The larvae have been taken as far south as lat. 48°, and eastwards up to the mouth of the English Channel, but they are absent from the tongue of low salinity water continuous with the St George's and Bristol Channels. Their distribution in the remaining area can be correlated with the cyclonic circulation.

The larvae obtained from the Celtic Sea are specifically identical with those found off the west coast of Ireland and with the typical A. albida of the Faroe-Hebrides region.
Further Observations on Fish Growth in a Fertilized Sea Loch (Loch Craiglin)
Authors: Gross F.
Published: May 2009

Flounders grew much more slowly in 1944 than during the previous 2 years. From October 1943 to October 1944 their mean size increased from 7·9 cm., 6·8 g., to 12·7 cm., 23·6 g., an increment which was if anything smaller than under normal conditions. The reason for the reduction in growth rate is attributed to the increasingly unfavourable hydrographic conditions resulting from the prolonged closure of the dam, in particular to the high H2S concentration, the high pH and the low oxygen concentration of the water.

In the autumn of 1944 the sluice gate of the dam was opened for several months. In 1945/46 the growth of stock III flounders was very rapid. They reached a mean size of 32·3 cm., 409 g., in March 1946 and 36·8 cm., 580 g., in March/April 1947. Native flounders reached a mean size of 30·6 cm., 353 g., in 2 years.
The Thixotropy and Dilatancy of a Marine Soil
Authors: Chapman Garth
Published: May 2009

Modifications are described to the penetrometer originally designed by Chapman & Newell (1947) for the measurement of the resistance to penetration of marine soils.

An account is given of qualitative and quantitative tests made during the study of the thixotropy and dilatancy of the muddy sand of theArenicolaregion of the shore at Whitstable. The results of tests made with the dilatancy viscometer originally used by Freundlich & Röder are shown not to be in clear agreement with the observed behaviour of the soil.