bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on the biology and submergence behaviour of some littoral beetles
Authors: Evans P. D. , Ruscoe C. N. E. , Treherne J. E.
Published: May 2009

The four species studied (Bledius spectabilis, Heterocerus fenestratus, Dichirotrichus pubescens and Cillenus lateralis) are most commonly found in a region delimited by the anaerobic mud of the lower bank and the dense marsh bordering the drainage channels in tidal salt-marshes at Scolt Head Island, Norfolk.

Experimental submersion of the beetles in sea water was found to induce an apparent anoxic condition which was associated with a drastic reduction in oxygen consumption. On return to air there was a large increase in oxygen consumption characteristic of an appreciable oxygen debt.

The use of the physiological responses to submergence as an indicator of effective contact with water revealed that their subterranean mode of life largely prevents direct exposure of the beetles to sea water in natural conditions. A significant proportion of Heterocerus fenestratus were, however, found to be vulnerable to flooding by sea water during tidal coverage of the burrow system.

These results are considered in relation to the observations made on the behaviour
and burrowing activity of the various species.
The biology of Laminaria hyperborea. VI. Some Norwegian populations
Authors: Kain Joanna M. , Jones N. S.
Published: May 2009

INTRODUCTION

Much of the rocky coast of Norway is known to form a favourable habitat for Laminaria hyperborea (Gunn.) Foslie. In June and July 1965 observations of this species and its competitors were made both in an area near Espegrend (60° 16.23′ N, 5° 13.42′ E), 15 km south of Bergen, and near Tromso (69° 39.2′ N, 18° 57.6′ E) for comparison with populations round the Isle of Man.
Sperm activation and fertilization in Balanus balanoides
Authors: Walley L. J. , White F. , Brander K. M.
Published: May 2009

INTRODUCTION

Balanus balanoides (L.) is a cross-fertilizing hermaphrodite. Insemination takes place in November in North Wales. Spermatozoa are deposited in the mantle cavity of a receptive individual by the extended penis of a neighbouring ‘acting male’. If a receptive individual – that is one that will accept insemination – is examined before oviposition takes place, the oviducal glands are found to be distended by a clear fluid (Walley, 1965). Oviposition follows insemination and fertilization is external, taking place within the confined space of the mantle cavity. The oocytes enter the mantle cavity, via the paired oviducal glands, and become enclosed in a pair of thin membranes. These membranes, enveloping the egg masses, are formed by distension of the elastic sacs secreted by the oviducal glands (Walley, 1965) and the spermatozoa have to pass through them in order to fertilize the eggs. If spermatozoa which have been deposited in the mantle cavity of a receptive individual are removed and examined before oviposition begins, they are immotile. If, however, they are examined several minutes later, during oviposition, they are found to be swimming vigorously (Barnes & Crisp, 1956): they have apparently been activated. The work described in this paper yields some information on the activation of the spermatozoa in B. balanoides, supplements recent work on the structure of cirripede spermatozoa (Brown, unpublished2; Turquier & Pochon-Masson, 1969; Bocquet-Vedrine & Pochon-Masson 1969; Munn & Barnes, 1970), and fixes the time within the sequence of maturation divisions of the oocyte at which fertilization takes place.
The First Leslie Cooper Memorial Lecture Given at Plymouth on 10 April 1989 Gaia
Authors: Lovelock J.E.
Published: May 2009

I am pleased and honoured to have been asked to give the first of the lectures in memory of Dr Leslie Cooper. I was especially moved by the thought that the invitation was made knowing that I should almost certainly choose Gaia as the topic of my lecture. I know that many of you, especially biologists, think that the Gaia hypothesis is either trivial and untestable or else a mere reiteration of conventional wisdom in poetic terms. Hardly a topic with which to commemorate Leslie Cooper's memory.

You will be relieved to know that although Gaia is the theme of my talk, I shall try not to be overly partisan or dogmatic. My objective is to use Gaia theory to illustrate a top-down approach to earth and life science and try to contrast it with the bottom-up approach which is conventional in the earth and life sciences.
Narcotising Sea Anemones
Authors: Moore S.J.
Published: May 2009

Many techniques have been devised to overcome certain problems encountered when narcotising actiniarians. From these a few have been selected as being at least partly successful. Further modifications to these narcotising methods have been introduced in order to block more effectively the nervous pathways responsible for secondary contraction reactions. Until now, perfectly expanded specimens have been achieved largely by chance. This paper records experimental results and arising problems as a contribution to a better understanding of the process and a more consistent rate of success.
Mytilicola Intestinalis (Copepoda: Cyclopoida): A Ten Year Survey of Infested Mussels in a Cornish Estuary, 1978–1988
Authors: Davey J. T.
Published: May 2009

The progress of the copepod Mytilicola intestinalis Steuer from obscurity in Mediterranean mussels, Mytilus galloprovincialis, to notoriety as the scourge of European blue mussels, M. edulis, has been well documented (e.g. Lauckner, 1983). However, a reputation as a pest in a commercially important species is not easily overturned and operators in the economic sphere must be expected to proceed with circumspection where their livelihoods are.at stake. In the UK, Parliamentary Orders still control the deposition and movements of seed shellfish in the attempt to contain the spread of the copepod.
Shell Shape Variation in Littorina Saxatilis and L. Arcana: A Case of Character Displacement?
Authors: Grahame J. , Mill P.J.
Published: May 2009

It is now well established that there are several species in the group of rough periwinkles inhabiting European rocky shores. The usual consensus agrees on four, namely Littorina saxatilis (Olivi), Littorina arcana Ellis, Littorina nigrolineata Gray and Littorina neglecta Bean. The first two species are particularly difficult to distinguish in the field and have received much attention. Recent work indicates that the ovoviviparous L.saxatilis is a very variable species living in a wide range of habitats (e.g. Janson, 1985) and that, although it is close to the oviparous L. arcana in shell morphology and in genotype, the two are separate species (Ward & Warwick, 1980; Ward & Janson, 1985), and not reproductive morphs of the same species.
On levels of calcium and of vitamin A aldehyde in the blood of arctic cod
Authors: Woodhead P. M. J. , Plack P. A.
Published: May 2009

Cod (Gadus morhua L.) from the Arcto-Norwegian stock were caught during their gonadal maturation cycle, and plasma samples from individual fish obtained for the determination of total calcium and vitamin A aldehyde (retinal + dehydroretinal). The concentrations of these two substances in the plasma of female cod caught during January–March were significantly correlated r = 0·728, P < 0·001, and this result supports the hypothesis that the increases in concentrations of plasma calcium and vitamin A aldehyde during the period of ovarian maturation may be controlled by the same mechanism. In September, just prior to ovarian maturation, and in October, at the beginning of maturation, there was no correlation between the concentrations of the two substances.
The surface swarming ofPolybius henslowi[Brachyura: Portunidae]
Authors: Allen J. A.
Published: May 2009

A dense population ofPolybius henslowiLeach 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 thatPolybiustends 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.
Observations on the population ofScoloplos armigerat Whitstable
Authors: Gibbs P. E.
Published: May 2009

The population ofScoloplos armigerO. F. Müller at Whitstable was investigated from January 1964 to April 1965. Initially the population density was high, being over 600/m2, but the numbers sharply declined during the summer of 1964 and by the following winter the density had dropped to under 100/m.2In addition to this decline, the population structure changed, and the overall effect was a marked reduction in the fecundity of the population. The cause of the high mortality in the summer of 1964 is unknown.
Bioluminescence in planktonic halocyprid ostracods
Authors: Angel M. V.
Published: May 2009

Bioluminescence has been observed in 11 halocyprid ostracod species, and the sites of secretion are described.

Bioluminescence in cypridinid ostracods has been thoroughly investigated (Harvey, 1952). However, since the original suggestion that the edge glands in the carapace of halocyprid ostracods secrete luminescent substances (Claus, 1891), only a single observation has been made confirming this suggestion on Conchoecia curta ( =clausi) (Müller, 1894).
Strombidiid ciliates from coastal waters near Kingston Harbour, Jamaica (Ciliophora, Oligotrichia, Strombidiidae)
Authors: Lynn Denis H. , Gilron Guy L.
Published: May 2009

Fifteen marine strombidiid species were measured and identified after protargol staining of bottle-cast samples collected during an annual study of the ciliate microzooplankton in the Caribbean Sea. Nine of these are described herein as new species. One new species from the genus Tontonia, T. simplicidens sp. nov., is defined, based on the pattern of the girdle and ventral kinety. Six new species of Strombidium, S. bilobum sp. nov., S. eurystomum sp. nov., S. ioanum sp. nov., S. maedai sp. nov., S. pollostomum sp. nov. and S. sphaericum sp. nov. are defined, based on cell size and shape, the arrangement of the oral ciliature, and the nature of the macronucleus. One new strombidiid genus Cyrtostrombidium gen. nov., is defined by the presence of a unique oral ‘basket’ and the absence of the ventral polykinetidal zone. Two species of Cyrtostrombidium, C. longisomum sp. nov. and C. wailesi sp. nov., are distinguished, based on cell size and macronuclear structure. Assemblages of six previously-described strombidiid species, S. constrictum, S. dalum, S. epidemum, S. inclinatum, S. wulffi, and Laboea strobila are also briefly described.
Heterotrophic flagellates and other protists associated with oceanic detritus throughout the water column in the mid North Atlantic
Authors: Patterson David J. , Nygaard Kari , Steinberg Gero , Turley Carol M.
Published: May 2009

Heterotrophic protists, mostly flagellates, encountered in association with marine detritus from various collections in the mid North Atlantic are described. About 40 species have been identified and are reported. Taxa reported here for the first time are: Caecitellus gen. nov. (Protista incertae sedis) and Ministeria marisola gen. nov., sp. nov. (Protista incertae sedis). The flagellates form a subset of the community of heterotrophic marine flagellates encountered in more productive marine sites. Most species are bacterivorous and small. The community extends to the ocean floor but the diversity is reduced in samples taken from greater depths. The decline in species diversity is linked also to a decline in numbers of individuals. We discuss these changes in relation to food supply and pressure effects.
Life history analysis of five dominant infaunal polychaete species from the continental slope off North Carolina
Authors: Blake James A.
Published: May 2009

Observations were made on the reproduction and life history of five species of polychaetes collected from the continental slope off North Carolina, USA. Three species were studied at a 2000-m lower slope station off Cape Lookout (Aurospio dibranchiata, Microrbinia linea, and Pholoe anoculata) and the other two at a 600-m upper slope station off Cape Hatteras (Cossura longocirrata and Scalibregma inflatum). Aurospio dibranchiata, a surface feeding spionid, exhibited seasonally in egg diameter and size-frequency data, with the larger sizes occurring in late summer months. Pholoe anoculata, a small carnivorous scale worm, did not exhibit any evidence of seasonality in size-frequency data at the 2000-m station. Sexually mature specimens were absent from this population, but were present at shallower slope depths, indicating year-round recruitment into the lower slope from middle and upper slope populations.
The macrobenthic infauna off Sellafield (north-eastern irish sea) with special reference to bioturbation
Authors: Swift D. J.
Published: May 2009

Between 1983 and 1989,66 stations in the north-eastern Irish Sea offshore from Sellafield, Cumbria, were sampled by Reineck box corer to assess the abundance and distribution of the benthic macro-infauna. A total of 40 taxa was identified, of which the predominant group was polychaetes. Cluster analysis of the abundance data showed a division into three station clusters. Simple discriminant analysis showed that the three clusters were correlated (P<0.01) with sand, silty sand and sandy silt sediments. However, the three station groups did not show any clear pattern of characterizing taxa with sediment classification. The bioturbating potential of each taxon is reviewed. A method of weighting abundance data by a factor representing an estimate of individual taxon bioturbating potential is also suggested. This technique is illustrated and discussed by using the weighted data in a further cluster analysis to identify probable areas of high inf aunal bioturbation off Sellafield.
Reproduction and growth of Sphaerechinus granularis (Echinodermata: Echinoidea) in southern Brittany
Authors: Guillou Monique , Michel Christine
Published: May 2009

Although the English Channel is the northern limit of the latitudinal range of Sphaerechinus granularis (Echinodermata: Echinoidea), this echinoid can produce locally high densities in Brittany, such as in the Glénan Archipelago (Bay of Concarneau) where a small-scale fishery has been exploited since 1985. The reproductive cycle, the growth patterns and the migration of the species in this area were studied from 1988 to 1992. Sphaerechinus granularis presents an annual reproductive cycle with a major spawning in the early spring. But inter annual variability in the time when spawning starts can be observed. A relationship is established between the date of onset of spawning and the climatic conditions during the whole period of gonadal growth. Recruitment is isolated in time and reflects the reproductive cycle.
Feeding habits of oplophorid shrimps in the deep western Mediterranean
Authors: Cartes J. E.
Published: May 2009

Diets of the two deep-sea species of Mediterranean oplophorids were studied by the analysis of 244 foregut contents of Acanthephyra eximia and 69 of Acanthephyra pelagica. All the specimens were collected on the deep slope (between 610 and 2261 m) using an OTSB-14 bottom trawl.

The diet of A. pelagica consisted of small mesopelagic fishes (Cyclothone braueri, Myctophidae) and bathypelagic crustaceans (Gennadas elegans, Pasiphaea multidentata, Eucopia hanseni, Meganyctiphanes norvegica, hyperiids). In contrast, A. eximia was an important scavenger, feeding on fish remains. Benthic species (polychaetes, Calocaris macandreae, gastropods, etc.) were also detected in its diet. There was little dietary overlap between the two species. In A. eximia bathypelagic decapods were important only in the diet of large specimens. In small specimens the acquisition of decapod prey was not attributable to active hunting. On the lower slope A. eximia was more detritivorous, and predatory activity was lower. This trend was most distinct in small and medium-sized individuals, which predominate at that level.
Imposex in Australian Conus
Authors: Kohn Alan J. , Almasi Kama N.
Published: May 2009

Previously unknown in Conus (Mollusca: Gastropoda) and poorly documented in the Australian region, imposex is demonstrated in 80% of females of six Conus species from Rottnest Island, Western Australia. In no case were the effects sufficiently severe to cause sterility, and reproduction appeared normal. Specimens from the same location preserved in 1975 were unaffected. With more than 500 species, Conus is the largest genus of marine molluscs. Because many species are conspicuous, widely distributed, and occur in populations whose past densities are known, they could serve as monitors of artificially induced pseudohermaphroditism and an early warning of future population responses to pollutants in marine environments at low latitudes.
Otolith Microstructure of the Lesser Sandeel, Ammodytes Marinus
Authors: Wright P. J.
Published: May 2009

Daily increments were demonstrated in the sagittae of the lesser sandeel, Ammodytes marinus, maintained in outdoor enclosures. Daily increment formation was also inferred for wild sandeels from an analysis of changes in age composition within a series of field samples. A comparison between sagitta microstructure and morphological development of larval and juvenile sandeels indicated that the first sagitta increment was formed around the time of hatching. Yolk-sac absorption and larval metamorphosis were accompanied by changes in otolith microstructure.

The lesser sandeel, Ammodytes marinus (Raitt), is important as a prey item for many species of fish, seabirds and marine mammals (Furness, 1990) and supports major fisheries in the North Sea (Anon., 1991). However, little is known about the ecological processes affecting year-class strength in this species. Otolith microstructure has been demonstrated to be a potentially useful tool for investigating early survivorship in fishes, since otoliths may provide a chronological record of early growth and life-history events (see Campana & Neilson, 1985). This paper examines the usefulness of otolith microstructure for studies of sandeel growth, from investigations of increment periodicity and a comparison between otolith microstructure and morphological development.
The Taxonomic Status of Littorina Neglecta: A Comment to Grahame, Mill, Double and Hull
Authors: Johannesson K. , Johannesson B.
Published: May 2009

In a short communication Grahame et al. (1992) argue against our finding that Littorina neglecta Bean is an ecotype of Littorina saxatilis (Olivi) rather than a separate species (Johannesson & Johannesson, 1990b). Unfortunately, Grahame et al. (1992) have miss-represented our earlier paper, and we feel the need to refute their arguments.

In populations from north-western Europe we studied morphological characters used to separate Littorina neglecta from L. saxatilis. We found that intermediate shapes were common and, furthermore, we found no close coupling among characters used to define L. neglecta (Johannesson & Johannesson, 1990a). We further analysed the genetic variation in five strongly polymorphic allozyme loci. In four loci we found a pattern that indicated that L. neglecta is not reproductively isolated from L. saxatilis. In the fifth locus, Aat-1, we found consistent differences between populations of L. neglecta (from the low shore) and L. saxatilis (from the high shore). Similar differences were observed between low and high shore populations in Sweden where, however, no snails of neglecta-type were present.
Marine-feeding otters (Lutra lutra) in Norway: seasonal variation in prey and reproductive timing
Authors: Heggberget Thrine Moen
Published: May 2009

Diet and food resources of marine-feeding otters (Lutra lutra, Mammalia) were studied along the coast of central Norway, where otters breed in all seasons. The fish and crab fauna in the 0–10 m depth zone where otters forage were sampled and otter spraints collected monthly for three years. Results were compared with published data from Shetland where otters breed mainly in summer. Most of the main prey species showed significant seasonal variation in numbers or biomass, which tended to be low in late winter or spring. The variations during the rest of the year were not synchronized between species. The combined density of the main prey species of Shetland otters, which peaked during summer, was low in Norway. This species group, eelpout (Zoarches viviparus), butterfish (Pholis gunnellus) and rocklings (Ciliata sp., Gaidropsarus sp. ), also constituted a smaller fraction of the total catch in Norway than in Shetland.) and bullrout (Myoxocephalus scorpius), constituted a larger fraction of the catch in Norway than in Shetland. Thus the otter's food resources on the Norwegian coast were seasonal, being minimal during the early months of the year, but with no clear maximum season as there is in Shetland. This may explain the differences in reproductive timing in the non-seasonal or autumn and winter species, cod (Gadus morhua.
Variation in the tidal migratory behaviour and rhythmic light-responsiveness in the shore crab,Carcinus maenas
Authors: Warman C. G. , Reid D. G. , Naylor E.
Published: May 2009

The distribution of shore crabs,Carcinus maenas(L.), within the intertidal and shallow subtidal zones of a rocky shore in the Menai Strait, North Wales, was recorded regularly by diving throughout the tidal cycle. Samples were also obtained by searching the shore during low tide and by collecting crabs in baited pots. It was found that the smaller individuals (<35 mm carapace width) in the population tend to remain within the intertidal throughout the tidal cycle whilst others, mainly the red-coloured adults, appear to remain permanently below low-water mark. The remainder of the population, predominantly green males larger than 35 mm carapace width, migrate upshore with the flood tide and downshore again with the ebb. The behaviour of C.maenason the shore appears to be affected, at least in part, by a tidally rhythmic pattern of responsiveness to directional light which is seen in freshly collected crabs in the laboratory.
The Effect of particle size on the burying ability of the brown shrimpCrangon crangon
Authors: Pinn Eunice H. , Ansell Alan D.
Published: May 2009

The burial mechanism ofCrangon crangonwas examined in detail using high-speed video-recording equipment. Four stages of burial were identified which were associated with three modes of burial. As the mode of burial changed, a change in the angle of substratum penetration was also noted.

The effect of particle size on the burying ability of three discrete size classes of shrimp was examined using both artificially graded and naturally occurring sediments. Particle size was found to be a major influencing factor on the degree of burial achieved by C.crangon, but no significant effect of shrimp size on burying ability was found over the size range tested.
Reproductive cycle and energetic cost of reproduction of the neogastropod Buccinum undatum in the Irish Sea
Authors: Kideys A. E. , Nash R. D. M. , Hartnoll R. G.
Published: May 2009

The annual reproductive cycle and cost of reproduction of the common whelk, Buccinum undatum L. (Gastropoda: Prosobranchia) were studied off Douglas, south-east of the Isle of Man. Sexual maturity was reached at 60–70 mm shell length. Two years of laboratory observation and field data indicated an autumn to mid-winter breeding season. Egg-laying occurred in the laboratory mainly between December and January, and hatching of juveniles between April and early May, 3–5 months after spawning. The cycles of testis and ovary development were very similar, especially during the breeding period. The annual energy invested in reproduction was estimated to be at least 4.1 kj m-2. The investment by females (3.84 kj m-2 y-1) was much greater than by males (0.26 kj m-2 y-1).
Dynamics and growth of a bivalve, Abra tenuis, at the northern edge of its distribution
Authors: Dekker R. , Beukema J. J.
Published: May 2009

The small bivalve Abra tennis (Montagu) (Bivalvia: Semelidae) reaches the north-eastern edge of its range in the Wadden Sea near the Dutch/German border. In the Wadden Sea it is restricted to a narrow intertidal zone close to the high-water level. Data are reported from a population at Balgzand, in the south-westernmost part of the Wadden Sea, which has been monitored for two decades. This population showed a strongly fluctuating density and was seemingly absent for more than three years following three severe winters in succession. Over-winter survival in adults was greater during mild than cold winters, and close to zero during all winters that were colder than average. Recruitment was higher in warm than in cold summers. Growth was more rapid in warm than in cold spring-summer periods. In warm years growth rates were higher than in more southern locations, and values for maximum size and life span were relatively high.
Spatial and temporal distribution and recruitment of echinoderm larvae in the Ligurian Sea
Authors: Pedrotti M. L.
Published: May 2009

Seasonal and annual variations in the distribution and abundance of echinoderm larvae (early to post-larvae of principally echinoids and ophiuroids), were determined from a series of plankton net tows taken at three stations in the Bay of Villefranche (France) and along a radial transect of 28 nautical miles (52 km), from the Bay to half-way to Corsica, between 1984 and 1988. Spatial distribution of six echinoderm species have been mapped. For the echinoids,Paracentrotus lividusandArbacia lixula, spawning takes place twice a year and appears to be synchronous because larval cohorts were comprised of distinct age-classes both near and far from the coast. Recruitment for these species is, therefore, thought to occur at well-defined periods. In contrast, the ophiuroid species studied (Amphiura filiformis, Ophwthrix fragilis, Ophiopluteus bimaculatusandO. compressus) spawn several times per year with a relatively short period in late spring and a prolonged spawning between the end of autumn and winter. These later results are consistent with the presence of mixed size-classes of larvae either from the nearby coast or offshore. Recruitment for these ophiuroids appears to be much more variable and spread over time.
Redescription of the overlooked crustacean isopod genusXenuraega(Aegidae, Flabellifera)
Authors: Bruce Niel L.
Published: May 2009

The genusXenuraegaTattersall, 1909, has been overlooked for most of this century. The rediscovery ofXenuraeganow brings the number of genera of Aegidae to six. The genus and the type species X.ptiloceraTattersall, 1909, are described in detail.Xenuraegais characterized by the following apomorphies: antennal flagellum extending beyond pleotelson; mandibular incisor absent, distal mandibular margin fused to cephalon; pleon abruptly narrower than pereon, pleotelson small, not concealing pleopods; uropod exopod reduced to short stub, endopod elongate, styliform, nearly as long as body; pleopods 1–5 not contained within or concealed by pleon and pleotelson.
A preliminary account of the general and enzyme histochemistry ofSiboglinum atlanticumand other Pogonophora
Authors: Eve C. , Southward A. J.
Published: May 2009

An account is given of the distribution of certain polysaccharides, lipids and proteins in the tissues ofSiboglinum atlanticum,a uni-tentaculate pogonophore collected from depths of 1300–1500 m on the continental slope. The histology of the various glands and cells is described, and the structure and histochemistry of the tentacle compared with that of three multitentaculate species of pogonophores collected from similar habitats.

Esterases hydrolysinganaphthyl acetate and o-acetyl-bromoindoxyl are found in most tissues ofSiboglinumafter formalin fixation. An eserine-sensitive esterase was present in the dorsal ciliated band, mostly close to the bases of the cilia. An organophosphorus-resistant esterase was widely distributed as scattered particles in the subcuticular region of the epidermis of the tentacle and anterior end. The other tissues, including the epidermal glands, blood vessels, muscles and peritoneum, contained a simple B-esterase which was closely associated with lipid globules; the nerve fibre B-esterase was not associated with lipid and its apparent sensitivity to copper illustrates one aspect of the difficulty of applying mammalian esterase subdivisions to invertebrates. Lipids form the main food reserve, and appear to have a dominant role in the metabolism.

Pogonophores do not possess a gut at any stage in their life, and must take up food through the epidermis, whether or not it is first digested. The epidermal glands do not appear to have any digestive function. The multicellular pyriform glands secrete fibres of chitin and acid mucopolysaccharide, and produce the major part of the tube in which the animal lives. The unicellular glands are of several types, but most of them, apart from some simple mucous glands, appear to take part in tube formation, secreting mucopolysaccharides or mucopolysaccharides and protein.
The attractive factor of intertidal sands toProtodrilus symbioticus
Authors: Gray John S.
Published: May 2009

In simple choice experimentsProtodrilus symbioticusGiard, an interstitial archiannelid, was shown to prefer the sand from its habitat in the natural state to the same sand altered by various physical or chemical treatments. The attractiveness of a sand was measured as the ratio of the number ofProtodrilusentering the experimentally treated sand to the number entering the natural sand in simple or multiple choice experiments.

The attractiveness of natural sand toP. symbioticuscould be destroyed almost completely by acid cleaning, by heating in water above 50° C or by drying at any temperature.

Treating attractive sand with formalin or cetyltrimethylammonium bromide rendered it about half as attractive as before treatment. Heating natural sand in water to 40°C and keeping it in fresh water for 18 h had no effect on the attractiveness. Sands that have been made unattractive by acid cleaning or drying can be restored to an attractive state by soaking in sea water. Typically acidcleaned sands recovered up to half and dried sands almost the whole of the attractiveness.

Inoculation of naturally occurring sand bacteria to highly unattractive acid-cleaned sand restores the attractiveness completely. Autoclaved sand to which a culture ofPhaeodactylumhad been added was preferred to sand treated with cultures ofDunaniellaandChlorella.An ordinary culture ofPhaeodactylumcontaminated by bacteria restored the attractiveness to autoclaved sands more effectively than a bacteria-free culture.

Sands restored by inocula of natural sand bacteria, soil bacteria andPseudomonassp. were preferred to those treated withCorynebacterium erythogenes, Flavobacteriumsp. andSerratia marinorubraand these were preferred to control sands kept in sterile sea water.
Vitamin B12and Marine Ecology III. An experiment with a chemostat
Authors: Droop M. R.
Published: May 2009

A 250 ml. chemostat has been used to measure the parameters of vitamin B requirement in the chrysomonadMonochrysis lutheri.

The yield constant wasca.0·25 × 10 cells/μμg., i.e. one-third of the figure previously measured in batch cultures.

The saturation constant lay between 2 and 6 μμ/ml., i.e. at least twenty times the figure indicated by previous batch culture measurements.

Internal inconsistencies in the chemostat's operation indicate the presence of factors not accounted for by theory.

It is argued that only factors analogous to the release of protein-bound vitamin into the medium could in principle account for all the discrepancies.
Direct development in a Nudibranch, Cadlina laevis, with a discussion of developmental processes in Opisthobranchia
Authors: Thompson T. E.
Published: May 2009

Cadlina laevis (L.) is the first British species of nudibranch shown to possess direct development. The embryo leaves the egg-capsule approximately 50 days (at 10° C) after oviposition, and resembles the adult in the general form of the body. Sufficient food reserves remain to sustain life and apparent growth for more than 1 week of benthic life. A vestigial veliger phase is passed through within the egg-capsule. The shell, velum, mantle, and metapodium-rudiment resemble transitorily those organs of opisthobranch veliger larvae, but certain veliger structures (larval kidney, velar locomotor and pedal cilia) are vestigial in Cadlina, and others are altogether absent (operculum, larval retractor muscle, subvelar ridges, metapodial mucus-gland, pedal sensory cilia, and nephrocysts).

In the Opisthobranchia three distinct development types can be recognized. Type 1 includes those species which possess planktotrophic veliger larvae. Type 2 comprises the species which have lecithotrophic larvae (in the sense employed by Ockelmann, 1965). Type 3 species have direct development, in which many veliger structures may be briefly recapitulated before hatching. Species of type 3 possess eggs of the largest sizes, species of type 2 in general have smaller eggs, while species of type 1 possess the smallest eggs. There is a positive correlation between egg size and the length of the embryonic period, and an inverse correlation between both and batch size. Within any development-type, the largest species tend to produce larger eggs in greater numbers. Within any species, the largest individuals tend to produce more eggs than do the smaller individuals; egg size varies little through the geographical range.
Branchiostoma lanceolatumlarvae: Some experiments on the effect of thiouracil on metamorphosis
Authors: Wickstead J. H.
Published: May 2009

Larvae ofBranchiostoma lanceolatum(Pallas), of a late pre-metamorphosis stage and characterized by a bright fluorescent green around the ilio-colonic ring, were taken in the Plymouth area plankton in August 1965.

Adults were kept in 0.04% thiouracil to determine the general effect at this concentration. It was lethal over a period of weeks.

The larvae were kept in the dark at a constant temperature of 10° C, individu-ally or in pairs, in 0.04%, 0.02%, 0.01%, 0.005% and 0.0025% thiouracil, in saturated solutions and suspensions of thyroxine and triiodothyronine, and in ordinary sea water. Solutions were changed weekly. The flagellateDunaliella primolectaButcher was supplied as food.

All the larvae metamorphosed at approximately the same time and rate, two exceptions being that 0.04% thiouracil was a more obviously toxic concentration and the thyroxine and triiodothyronine larvae were rather more precocious in their metamorphosis.

It is suggested that metamorphosis is a ‘triggered’ process and is self-sustaining. Thus once it has begun it cannot be delayed or accelerated significantly. All the larvae caught were at a stage when this ‘triggering’ had been released.

It is considered possible that the metabolism of the larva and the initiation of metamorphosis is controlled by a secretion of the club-shaped gland.

INTRODUCTION

The position of the amphioxides larva has already been discussed (Wick-stead, 1964). No clear demarcation could be made between the usual type of acraniate larva and amphioxides. It was suggested that the amphioxides was a giant larva, a phenomenon not uncommon in oceanic plankton.

Introduction

The position of the amphioxides larva has already been discussed (Wickstead, 1964).
Clone culture studies of a new rosalinid foraminifer from Plymouth, England and Wellington, New Zealand
Authors: Hedley R. H. , Wakefield J. St J.
Published: May 2009

A formal description ofRosalina leeisp.nov. (Foraminifera) includes an account of the great morphological variation found among adult agamonts obtained over a period of 14 months from clone cultures. Variation in chamber number, direction of coiling, overall shape, the degree of inflation of the final chamber and suture characters are detailed.
The biology ofCucumaria elongata(Echinodermata: Holothuroidea)
Authors: Fish John D.
Published: May 2009

A population ofCucumaria elongata(Düb & Kor.), found in muddy sand off the Northumberland coast, has been sampled from 1961 to 1964. Densities of more than 20 per m were common.

Cucumariais a suspension feeder, and uses its tentacles to trap suspended paniculate matter. In the absence of mucous glands or cilia on the tentacles, suspended matter is held fast in a covering of mucus which is produced by glands in the pharynx and oesophagus. Each time the tentacles are introduced into the pharangeal lumen in the course of feeding, they pick up a fresh complement of mucus.

The feeding behaviour is seasonal. During the early part of October the animals stop feeding, and remain dormant until late April/early May of the following year.

The results of monthly experiments to determine the oxygen consumption, percentage of total lipid and the volume/dry-weight ratio, have led to the conclusion that during the winter monthsCucumariahibernates.

The effect of temperature on the feeding behaviour is discussed.

Regular quantitative sampling has shown thatCucumariais slow growing, and over the area surveyed, four different age-groups were found. These have been designated groups I, A, B and C. Group I was estimated to be 2 years old; group A, 6 six years; group B, 8 years; and group C, 10 years old.

Although active sperm and apparently mature eggs were found in specimens collected as far back as 1962, there is no evidence to suggest that any of the age-groups has reproduced.
Studies in the biochemistry of cirripede eggs III. Changes in the amino-acid composition during development of Balanus balanoides and B. balanus
Authors: Barnes H. , Evens R.
Published: May 2009

The amino-acid composition of Balanus balanoides (L.) and B. balanus (L.) da Costa eggs during their development has been investigated. Protein accounts for 70–80% of the dry matter. The amino-acid composition of the eggs is similar to that reported for Calanus finmarchicus, for which reliable information is available. Loss of all amino acids takes place during development, but the relative amounts of glycine and alanine increase in the late stages. The rates of loss are far greater in B. balanus, where the eggs themselves develop more rapidly. In B. balanoides there is a distinct ‘ arrest’ in the rate of loss of amino acids at the H-stage; this is coincident with a similar arrest in the loss of other metabolites and in development. Loss of nitrogen from the eggs has been measured directly and the results compared with the values calculated from the analyses. In the early stages the agreement is good if allowance is made for the difference in temperature between the elution experiments and the natural environment.

Data have already been presented (Barnes, 1965; Dawson & Barnes, 1966) on the major biochemical constituents of the eggs of two common cirripedes, Balanus balanoides and B. balanus, and on changes in these constituents during development. It has been shown that protein nitrogen is lost throughout development and that the rate of this loss is greatest during the early stages; also that nitrogen utilization relative to that of carbohydrate is greater in B. balanus. The more rapid development of the eggs of the latter species gives rise to a greater rate at which all substrates are utilized, but the proportions disappearing—relative to the initial quantities—are not widely different; rather more is lost in the species that develops more rapidly.
Observations on an endozoic red alga
Authors: Boney A. D. , White E. B.
Published: May 2009

A description is given of a filamentous red alga which was found growing within a sponge collected from the sublittoral off Santander, Spain. The plant appears to be closely related to Acrochaetium spiculiphilum Dawson. A survey is given of the specific characters available for the typification of the known partially and completely endozoic Acrochaetium species, and some suggestions made on the more important lines of study.

Introduction

During the summer of 1957 some specimens of the keratinous sponge Haliclona were collected from the sublittoral off Santander, Spain, by Mr G. R. Forster. Certain of the specimens bore extensive areas of red, and on preliminary examination this colour was found to be due to the filaments of a red alga showing an extensive ramifying growth within the skeleton of the sponge. The drawings and cell measurements to be reported were made from the plant material by A. D. B. soon after its collection. This information has been retained pending a more comprehensive study of endophytic and endozoic red algae. Work is now in progress on these lines (mainly by E. B. W.), and a re-examination of the Santander material has enabled us to make a critical study of the data available for a precise typification of plants of this habit. Further, since the association of endozoic filamentous red algae with sponges appears to be of rare occurrence, any examples need to be fully described.

Description of Plant

The cells were of variable shape and size, and contained much-dissected parietal chromatophores (Fig. 1 a). Individual filaments tended to be closely packed together within the host (Fig. 1 b), and there was no extensive growth of erect filaments outside of the host material.
The genusEctocarpusin Britain II. The Free-living forms
Authors: Russell G.
Published: May 2009

Ectocarpus distortusandE. landsburgiiare shown to be conspecific and to constitute free-living ecads ofE. fasciculatus.It is therefore recommended that the two should no longer be regarded as true species although it is pointed out that the specific epithetE. distortusmay have priority overE. fasciculatus.If so, the entire complex, provisionally retained asE. fasciculatus, may have to be known asE. distortus.Meanwhile it is recommended that the list of BritishEctocarpusspp. be reduced to two, namelyE. fasciculatusandE. siliculosus.
Fiddler Crabs Use the Visual Horizon to Distinguish Predators from Conspecifics: A Review of the Evidence
Authors: Layne John , Land Michael , Zeil Jochen
Published: May 2009

Male fiddler crabs,Uca pugilator(Crustacea: Decapoda), respond to conspecifics by claw waving, and to predators by freezing or escape. In field experiments it was found that this distinction was not made on the basis of angular size and speed, nor was shape important. The remaining possibilities were either the absolute size of the stimulus, determined from angular size and distance, or the position of the stimulus relative to the horizon. To distinguish between these, a crab was placed in a glass dish, and moved black stimuli on a white background, at a distance of 22 cm. Stimuli below the crab's horizon hardly ever evoked escape. However, identical stimuli partially or wholly above the crab's horizon produced escape responses whose frequency varied with the angular size of the stimulus. Halving the distance of the stimulus showed that it was angular and not absolute size that determines escape frequency; and experiments with a tilted horizon showed that it is the position of the stimulus relative to the eye equator that is important, rather than the geographical horizon itself. It has been concluded that crabs categorize stimuli as dangerous or otherwise by their position relative to the crabs’ visual horizon.
Interspecific Comparisons of Genetic Population Structure in Members of theJaera AlbifronsSpecies Complex
Authors: Carvalho Gary R. , Piertney Stuart B.
Published: May 2009

Marked genetic differentiation in the intertidal isopod,Jaera albifrons(Crustacea: Isopoda) has been shown to occur on a scale of just a few metres on British shores. Allozyme electrophoresis at 21 enzyme-coding loci has been employed to examine genetic structure in other UK members of the complex (Jaera forsmani, J. ischiosetosa, J. praehirsuta), and explore the relationship between genetic diversity and perceived niche-width. Comparisons were made with the nonsibling speciesJ. nordmanni. Three subpopulations of each species taken from each of two shores on Anglesey, UK (subpopulations N=30) were assayed for electrophoretic variability. Data from 11 polymorphic loci (P0·95) demonstrated marked genetic differentiation in all populations ofJ. albifronsandJ. praehirsuta, and on one shore for each ofJ. ischiosetosaandJ. nordmanni, withJ. praehirsuta(GST=0·207) andJ. albifrons(GST=0·121) showing the highest genetic differentiation. In contrast,J. forsmaniexhibited population homogeneity on both shores studied. Genetic diversity ranged markedly across species (H0=0·165—0·040), with the two most widely distributed species,J. albifrons(H0=0·135) andJ. ischiosetosa(Ho=0·165) exhibiting the highest genetic variability, providing support for the niche-width variation hypothesis. Data indicate that although habitat fragmentation and direct development is associated with microgeographic differentiation inJaeraspp., localized factors such as habitat continuity and exposure to water movements determines the magnitude of such effects.
Sulphide Metabolism in Thalassinidean Crustacea
Authors: Johns A.R. , Taylor A.C. , Atkinson R.J.A. , Grieshaber M.K.
Published: May 2009

Sulphide occurs widely in marine sediments and is highly toxic to most organisms. Its principal poisoning effect occurs at extremely low concentrations and is the result of inhibition of mitochondrial cytochrome c oxidase. Mud-shrimps (Crustacea: Thalassinidea), construct burrows in sublittoral muddy sediments. The sediment in which they burrow is markedly reduced and conditions within the burrow are usually hypoxic and hypercapnic. Field measurements indicate that the shrimps may be exposed to potentially toxic levels of sulphide in the burrow water (range 0–206 μM, N=37). Laboratory experiments carried out onCalocaris macandreae, Callianassa subterraneaandJaxea nocturnahave shown that these species have a high tolerance of sulphide. An oxygen dependent detoxification mechanism exists to defend cytochrome c oxidase from sulphide poisoning. The main detoxification product of this mechanism is thiosulphate which accumulates rapidly even during brief exposures to low concentrations of sulphide. Sulphite also appears as a secondary detoxification product. Aerobic metabolism can be maintained even under severe hypoxia and toxic sulphide conditions. The mud-shrimps switch to anaerobiosis when the detoxification mechanism is saturated. These data indicate that mud-shrimps are physiologically adapted to tolerate elevated levels of sulphide that they may encounter in their natural habitat.
Comparisons of Social Structure of Columbus Crabs Living on Loggerhead Sea Turtles and Inanimate Flotsam
Authors: Dellinger Thomas , Davenport John , Wirtz Peter
Published: May 2009

Columbus crabs, Planes minutus (Crustacea: Brachyura) live in the open ocean attached to floating substrata including Sargassum, flotsam, and sea turtles. Eighty-two percent of 128 loggerhead turtles (Caretta caretta) checked, harboured a total of 172 crabs. Crabs inhabiting flotsam occurred in mixed sex groups of adults and juveniles, with a mean group size of 8.2 ±;11.8 (N=17). In contrast, crabs living on sea turtles around Madeira occur in smaller groups 1.6 ±0.5 (N=105) which are typically adult heterosexual pairs (61 out of 105). Crabs on turtles were bigger than on flotsam and a higher proportion of female crabs were brooding eggs. Columbus crabs exhibit different life history strategies depending on the substratum they inhabit.