bluuebunny/crossref_metadata_2025 huggingface dataset:
Marine triclads from the Plymouth area
Authors: Hartog C. Den
Published: May 2009

In 1962, 1964 and 1966 the author collected four species of marine triclads, viz.Procerodes littoralis(Ström),P. ireneaesp.nov.,P. lobata(O. Schmidt) andUteriporus vulgarisBergendal in the Plymouth neighbourhood. Each species is fully described. Attention has been given not only to internal characters, as the structure of the genital apparatus, but also to external features such as the shape of the head and the pattern of pigmentation, because these external characters are sufficient for the identification of the species. Further, the geographical distribution and ecological data have been recorded for each species.
The marine biological station of the University of Liverpool at Port Erin, Isle of Man: a new wing, and a new research vessel
Authors: Colman J. S. , Bowers A. B.
Published: May 2009

The origins of the Marine Biological Station go back to 1885, when Professor, later Sir William, Herdman organized the Liverpool Marine Biological Committee. The Committee conducted dredging excursions in the Irish Sea, and also set up a very small shore laboratory on Puffin Island (off Anglesey) from 1887 to 1891. In 1892 activities were transferred to two small stone buildings (which still exist—see Pl. III) on Port Erin Bay. After nine years these buildings had become quite inadequate to accommodate the growing numbers both of visiting naturalists and of vacation classes which were started at Port Erin in 1897, so a further move was made to the present site at the south-west corner of Port Erin Bay in 1902.

In 1919 the control and ownership of the Marine Biological Station was transferred from the L.M.B.C. to the University of Liverpool; until 1939 the Station formed part of the Department of Oceanography, from 1939 to 1949 it was part of the Department of Zoology, and since 1950 it has formed a separate Department of the University.

The original building of 1902, whose whole seaward frontage still remains virtually unaltered (Pl. I), consisted of a central public aquarium (now room 5 on Text-fig. 1) flanked by a sea-fish hatchery (now 8, 9) and a few small research rooms (2,3,4,6,7), with two sizeable laboratories for student classes on the first floor (45–47 and 28, 30–32 on Text-fig. 2). A very valuable asset consisted of three large open-air ponds which still, after 65 years, perform their original function of maintaining a breeding stock of some 200 adult plaice.
Recovery of intertidal benthic diatoms after biocide treatment and associated sediment dynamics
Authors: Underwood G. J. C. , Paterson D. M.
Published: May 2009

It appears that, under suitable conditions, diatom assemblages can respond very quickly to a toxic event. The data suggest an inoculum of cells from the water column can multiply rapidly. Sediment-inhabiting macrofauna are more seriously affected, reducing grazing restrictions on the developing diatom assemblages. The structure and behaviour of the sediment was intimately related to biological factors including bioturbation and biogenic stabilization in a complex and interdependent manner. Further work is now required on the interaction of grazing organisms and microbial communities in the dynamics of intertidal cohesive sediments.
Distribution and structure of sub-cuticular glands in the copepod Temora longicornis
Authors: Bannister N. J.
Published: May 2009

The calanoid copepod Temora longiornis (Müller) has sub-cuticular secretory glands located on both the body and swimming legs. The glands are tri-cellular, consisting of a secretory cell (producing a proteinaceous secretion) opening through a cuticular pore, a collar cell surrounding the neck of the secretory cell, and a duct cell which lines the pore opening. The possible function of the secretion is discussed.
Suspension feeding in larval crabs (Carcinus maenas)
Authors: Factor Jan Robert , Dexter Barbara L.
Published: May 2009

First-stage zoeal larvae of the green (shore) crab, Carcinus maenas (Crustacea: Brachyura: Portunidae), ingested three types of particles offered in sea-water suspensions. In experiments using two types of fluorescent particles (1–2 µm and 1–7 µm ) and living Dunaliella tertiolecta cells (5–7 µm), particles were ingested in at least 40% of the zoeae examined with brightfield, darkfield, and epifluorescence microscopy. These results suggest that green crab larvae may be capable of utilizing planktonic particles in the size range of bacteria, small algal cells, and organically-enriched detrital particles in their natural diet.
A new species of lugworm: Arenicola defodiens sp. nov.
Authors: Cadman P. S. , Nelson-Smith A.
Published: May 2009

A new species of lugworm Arenicola defodiens sp. nov. (common name ‘black lug’ or ‘runnydown’) is described from 148 specimens taken from intertidal sands around South Wales. Comparisons are made with the well-known and generally more common lugworm Arenicola marina (L.). To aid in diagnosis, a table illustrating differences in the genetics, ecology and morphology is also provided.
Developmental changes in the opacity of larval herring, Clupea harengus, and their implications for vulnerability to predation
Authors: Langsdale J. R. M.
Published: May 2009

The relative contributions of the eye, pigmentation (melanophores), and gut contents to the lateral body areas of herring larvae, Clupea harengus L., were measured using a combination of photography and computer image analysis. There was a power relationship between body area and body length (exponent 2.62) which was similar to that of the eye area (exponent 2.57) whereas the pigmented area increased at a greater rate (exponent 4.41). The area of the full gut relative to body length increased at an intermediate rate (exponent 3.04). Melanophores dilated under the effects of anaesthetic, increasing the projected pigment area of herring larvae by an average of 94% after 10 minutes of anaesthesia. These results are discussed in relation to the vulnerability of herring larvae to visual predation.
Histochemistry of the Bucco-Oesophageal Glands ofMytilus Edulis: The Importance of Mucus in Ingestion
Authors: Beninger Peter G. , Pennec Marcel Le
Published: May 2009

Histochemical techniques were used to investigate the possible role of the buccooesophageal glands in the blue mussel,Mytilus edulisL. (Mollusca: Bivalvia). No activity was observed for any of the eight major digestive enzymes tested; however, the glands contained large amounts of both neutral and acid mucopolysaccharides. These results confirm the importance of mucus in the ingestive process inM. edulis, and do not support the hypothesis of ingestion of particles suspended in water alone.

Until recently it was thought that the Bivalvia were the only class of molluscs in which some type of secretory gland of extracellular digestive function in the bucco-oesophageal region was totally absent (Table 1). However, in a study of the mode of particle ingestion in five species of suspension-feeding bivalves, an extensive glandular complex was reported in the bucco-oesophageal region ofMytilus edulisL. only (Beningeret al., 1991). Although these glands were observed to liberate secretions into the oesophageal lumen, it was not known whether they performed any digestive function.
Reply to Johannesson & Johannesson
Authors: Grahame J. , Mill P. J. , Double M. , Hull S. L.
Published: May 2009

Johannesson & Johannesson (1993) contend that we have misread their earlier paper (Johannesson & Johannesson, 1990). They write that it is only possible to use neutral loci to study genetic relationships in closely related taxa (Johannesson & Johannesson, 1993) and that, there-fore, they had dismissed the variation in Aat-1 when considering the taxonomic status of Littorina neglecta (Johannesson & Johannesson, 1993). However, in their earlier paper they write: & ldquo;This [the pattern of variation in Aat-1] indicates that the within-site differentiation at Aat-1 is caused by diversifying selection in the two different micro-habitats rather than to a reproductive barrier between neglecta and saxatilis type snails” (Johannesson & Johannesson, 1990, p. 94). Therefore, after dealing separately with the pattern of variation at four loci which are ‘presumably neutral’ (Johannesson & Johannesson, 1990, p. 96), the Aat-1 variation is considered by these authors in the context of a putative reproductive barrier. The argument is repeated at the beginning of the discussion in Johannesson & Johannesson (1990, p. 95).
Mixotrophy in marine species of Chrysochromulina (Prymnesiophyceae): ingestion and digestion of a small green flagellate
Authors: Jones Harriet L. J. , Leadbeater B. S. C. , Green J. C.
Published: May 2009

Species of Chrysochromulina (Prymnesiophyceae) were screened for their ability to ingest inert material and live cells of a small green flagellate. The species C. brevifilum showed a marked preference for the small green flagellate over carmine particles and the rate of ingestion of the flagellate was proportional to its concentration and inversely proportional to light intensity. Ingestion was also higher by phosphate-starved Chrysochromulina, and a clear predator/prey relationship was demonstrated with C. brevifilum clearly benefiting, in terms of growth rate, from the ingestion of the small green flagellate. Electron micrographs confirmed that digestion occurs.
The Effect of cell concentration on colony growth and feeding in the bryozoanCelleporella hyalina
Authors: Hunter E. , Hughes R. N.
Published: May 2009

The effects of cell concentration on colony growth and feeding behaviour were investigated in the polymorphic marine bryozoanCelleporella hyalina(Bryozoa: Cheilostomata) under controlled, laboratory conditions. We compared the relative zooidal composition of colonies cultured onRhodomonas baltica(Karsten) for seven weeks at 18°C. We observed the pharynx of active lophophores on sudden exposure to high cell concentrations, and recorded the length of feeding episodes and ingestion rates.

Colonies grew, reproduced and produced viable larvae at all levels of food supply, but performed optimally at 50–100 cells µl-1. Cell concentration influenced somatic parameters more than sexual, the latter being more closely associated with genotype. Relative somatic investment was greatest at 10 cells µl-1and least at 50 cells µl-1. The frequency of ovicells containing larvae remained at about 74% irrespective of food supply. Basal male investment was greatest at 10 cell µl-1, frontal male investment at 50 cells µl-1, and female investment at 100 cells µl-1.

Cell ingestion rates of previously starved zooids increased as a function of cell concentration, with an inverse relationship between length of feeding episode and concentration. Food particles were drawn from below the lophophore by lateral cilia, ciliary reversal brought them over the mouth, and ingestion then resulted from a pharyngeal current. These results suggest that, on exposure to high cell concentrations, bryozoans may exhibit specific behaviour.
Length, weight and condition factor ofAcartia clausi(Copepoda) in the eastern Mediterranean
Authors: Christou Epaminondas D. , Verriopoulos George C.
Published: May 2009

Cephalothorax length and dry weight of copepodite stages and adults of the planktonic copepodAcartia clausiGiesbrecht in the Saronikos Gulf, Greece, were measured. Length-weight relationships and condition factor were also determined. The results were based on 17 zooplankton samples collected between November 1989 and June 1990, a period in which the abundance ofA. clausiis significant. There was an inverse relationship between temperature and length, a pattern shown by many copepods. Temperature had the most significant effect on length, which was also affected by chlorophyll level. This strong temporal variation in length might possibly be considered as an adaptation ofA. clausito a continuously fluctuating environment. Length-weight regressions displayed high coefficients of determination (r2=0.98). Food, expressed as chlorophyll, affected the size and condition factor, and could act as a limiting factor on length and weight ofA. clausiin the study area.
Reproductive ecology of the velvet swimming crab,Necora puber(Brachyura: Portunidae), at Plymouth
Authors: Norman C. P. , Jones M. B.
Published: May 2009

Monthly samples of intertidal and near-shoreNecora puberwere collected over two years from a commercially unfished area around Plymouth (south-west England). A clear reproductive cycle, consistent between the two years, was observed, and relatively high numbers of ovigerous females were found from January to June. Zoeal release was estimated to occur from April to June. Ovigerous females had developing ovaries, indicating that sequential broods occur. During embryonic development, egg volume increased by 109%, and egg loss was significant, accounting for between 14 and 18.5% of initial brood number. Females suffering limb loss showed a further reduced brood size compared to females with a full limb complement. The sex ratio of immature crabs was 1:1, whereas the ratio for mature crabs was biased to males (1.46:1). Two sperm plugs were observed in 90% of early postmoult mature females, but 10% had only one or no plug intact, suggesting their failure to mate successfully. These results are reviewed in relation to the biogeography ofN. puberand with reference to the developing fishery in the United Kingdom.
Reproductive biology of Orchestia gammarellus (Crustacea: Amphipoda) living in a sewage treatment works
Authors: Jones M. B. , Wigham G. D.
Published: May 2009

A population of the supralittoral Orchestia gammarellus (Pallas) (Amphipoda: Talitridae), living in a percolating filter of a sewage treatment works has been studied over 12 months. The population showed a seasonal pattern of occurrence, few animals being collected during the winter. The sex ratio was biased significantly to females except during the breeding season when it did not deviate significantly from 1:1. Ovigerous females, never collected in high numbers (1–14 per month), were found from April to August, with peak occurrence in May/June. Juveniles were present throughout the year, but peak recruitment occurred in summer, following the period of reproduction by females. The smallest ovigerous female had a body length of 12.6 mm and the largest measured 20.0 mm. Egg numbers (5–31 per brood) increased with increasing female size and egg volume more than doubled during embryonic development. These findings are discussed in relation to the possible methods of colonization of this unique habitat and the influence of sewage on crustacean life-history traits.
Tryptic digestion of the serum immunoglobulin of the flounder, Platichthys flesus
Authors: Glynn P. J. , Pulsford A. L.
Published: May 2009

Purified serum immunoglobulin (Ig) from the flounder has been fragmented by treatment with trypsin at 56°C. The major product of the digestion is a protein which resists further degradation over a two-hour period. This fragment constitutes approximately 40% of the Ig molecule and on fully reducing SDS electrophoresis is composed of a single polypeptide chain of apparent molecular weight 33 kD. This is larger than the light chains and therefore indicates that the fragment is derived only from the heavy chains of the Ig molecule. If this fragment is composed of eight polypeptide chains, consistent with the tetrameric nature of the flounder Ig, then its molecular weight is 264 kD. Although its electrophoretic mobility on 4% non-reducing SDS gels suggests a molecular weight of 180 kD, densitometric data support the 264 kD value. The kinetics of the digestion indicate that the first event is the liberation of a 50 kD fragment which is a dimer of two 25 kD polypeptides and which may be a Fabµ fragment.
On the Occurrence of Parablennius Sanguinolentus (Pisces: Blenniidae) on the Portuguese Coast
Authors: Gonçalves Emanuel J. , Almada Vitor C. , Almeida Armando J. , Oliveira Rui F. De
Published: May 2009

In this paper we report for the first time the occurrence of Parablennius sanguinolentus in mainland Portuguese waters. Since this species is common in the Mediterranean and in the Bay of Biscay, there appears to be a distributional gap along the Portuguese coast. The present finding, together with recent data on the occurrence of several other blenniids in the Atlantic coast of the Iberian Peninsula, formerly supposed to be Mediterranean endemics, stresses the urgent need for detailed zoogeographical investigations on the inshore fish fauna of south-west Europe.

Parablennius sanguinolentus (Pallas, 1811) is widespread in the Mediterranean (Zander, 1986). On the Atlantic coast of Europe, however, it was known only from the Bay of Biscay where it is abundant in some places (Motos & Ibañez, 1979), from the north-west coast of Spain (Devesa et al., 1979) and recently from the Atlantic coast of Andalucía (Spain) (Rubio, 1991). It is also very common in the Azores, Madeira and Canary Islands if one assumes that P. parvicornis (Valenciennes, 1836) belongs to the same species, but this is as yet an unresolved issue (Zander, 1979; Almeida & Harmelin-Vivien, 1983; Bath, 1990; Santos, 1992). Although Zander (1986) presented a distributional map that includes the mainland Portuguese coast, no report on the occurrence of this species was known for this area. In a survey of the literature on the blennioid fishes occurring in Portuguese waters, we could not find a single citation that could possibly be ascribed to P. sanguinolentus for mainland Portugal (Oliveira et al., 1992).
Shell morphology and identification of early life history stages of congeneric species of Crassostrea and Ostrea
Authors: Hu Ya-Ping , Fuller S. Cynthia , Castagna Michael , Vrijenhoek Robert C. , Lutz Richard A.
Published: May 2009

Series of sequences of SEM micrographs are presented to elucidate species-specific shell features in larval and post-larval stages of four Ostreidae (Bivalvia) species (Crassostrea gigas (Thunberg), C. virginica (Gmelin), Ostrea edulis L., and O. equestris Say). The diagnostic characters, including hinge structure, shell shape, and the dimensions of the prodissoconch, are identified and summarized in a key at both generic and species levels. In larval Crassostrea the skewed, backwards-pointed umboned shells with two hinge teeth on each side of the provinculum are significantly different from the round, dorsally-directed umboned shell with fewer, remarkably asymmetric teeth of larval Ostrea.In C. gigas the dimensions of the provinculum are longer and narrower (56x10 µrn) than those of C. virginica (50x14 µm); the lengths of prodissoconch I and the provinculum are greater in O. edulis (168 µm and 86 µm, respectively) than in O. equestris (120 µm and 74 µm, respectively). The present study suggests that precise quantitative measurements are needed for differentiation of the studied congeneric oyster species.
Pycnogonids from southern Spain: Fauna 1 Project
Authors: Munilla Tomás
Published: May 2009

One hundred and twelve Pycnogonids belonging to 18 species are recorded from waters of 12–490 m depth on both sides of the Straits of Gibraltar. Twenty-three specimens are Mediterranean (8 species) and 89 are Atlantic (14 species).

Hannonia stocki and Ammothella gibraltarensis are new species. Pentapycnon geayi is new to European waters and Pycnogonum nodulosum, Ammothella biunguiculata and Callipallene spectrum are new from southern Spanish waters.

A total of 38 species has now been reported for southern Spain.

INTRODUCTION

There are only two published papers on pycnogonids from southern Spanish waters: Munilla (1988) reported on mediolittoral and shallow-water taxa (0–12 m), with 11 species collected, while Stock (1987) recorded 20 species from deeper waters (135–2110 m).

The present collection of 112 specimens, from shallow to moderately deep waters, was carried out in July 1989 aboard the B/O ‘Garcia del Cid’ during the Project FAUNA 1, conducted by the Museo Nacional de Ciencias Naturales in Madrid (CSIC).
Patterns of abundance and distribution of species in intertidal rock pools
Authors: Astles K. L.
Published: May 2009

Rock pools are unique and complex habitats in intertidal areas. Quantitative studies of assemblages in pools are few. Abundances and distributions of species in pools on a rock platform near Sydney (Australia) were sampled for two years. Pools of four different depths (5, 15, 30 and 40 cm deep) and up to four strata within each pool (0–5, 5–15, 15–30 and 30–40 cm, from the top of the pool) were sampled, replicated at four sites. The abundances and distributions of most species of plants and animals in pools did not differ between strata nor at different depths in the pools. Abundances of only three species, the encrusting alga,Hildenbrandia prototypusNardo, the trochid snail,Austrocochlea constricta(Lamarck) and the limpet,Cellana tramoserica(Sowerby) varied significantly between strata and depths. In contrast to other studies on rock pools, most species showed no significant temporal variations in mean abundances in the sites sampled. Significantly large, spatial and temporal, random fluctuations did, however, occur in abundances in individual pools. The consistency of abundances at larger spatial scales indicated that disturbance in these habitats may not be an important structuring process. The large variation between pools does, however, suggest that the history of each pool may have a more significant role in the character of its assemblage. Some implications of small-scale variability are discussed.
Heterozygote deficiencies in a cohort of newly settledMytilus edulisspat
Authors: Fairbrother J. E. , Beaumont A. R.
Published: May 2009

A cohort of newly settledMytilus edulis(L.) (Mollusca: Bivalvia) spat (mean shell length 530 µm) was collected from red filamentous algae at a site on the North Wales coast. After a period of growth in the laboratory, cellulose acetate and starch gel electrophoresis were used to investigate genotype frequencies at theGpi, Odh, Lap, Pgm, IdhandMpiloci. Individual testing of each locus, using the X2test revealed significant deficiencies of heterozygotes at thePgm, MpiandIdhloci. However, further testing using a sequential Bonf erroni test, designed to assess the probability of observing at least one significant result from a number of tests by chance alone, revealed that only the deficiency of heterozygotes atPgmandMpiloci was significant at the table-wide 95% level. Since post-collection mortality was <3%, these heterozygote deficits must have existed at the time of collection. The conclusion drawn is that heterozygote deficiencies in mussels are generated during the larval stage or at early settlement.
The importance of sulphur cross-links and hydrophobic interactions in the polymerization of barnacle cement
Authors: Naldrett Michael J.
Published: May 2009

Solidified adhesive (cement) of three balanid barnacles (Crustacea: Cirripedia) was dissolved using different concentrations of sodium dodecyl sulphate containing a reducing agent. The proteins were separated using SDS-PAGE and blotted onto polyvinylidene difluoride membrane for sequencing. Commonly occurring bands in the cement of each species were identified. One particular protein of 39 kD, found in the cement ofBalanus perforatus, has the following N-terminal sequence: TYFPVLSYG?SSSLAPVI, where the? is most likely cysteine. Quinones were not identified in the cement by either infra-red, ultraviolet-visible or solid-state nuclear magnetic resonance spectroscopy and the successful dissolution and sequencing of cement proteins mitigates against their presence. Cement contains a mixture of highly hydrophobic proteins which are cross-linked through cysteine residues. It is the combination of these two components which makes cement highly resistant to chemical degradation. As a result bacteria are usually absent from the cement, possibly further excluded from the porous core of the cement by its smooth outer crust.
The life-histories of the bivalves Montacuta substriata and M. ferruginosa, ‘commensals’ with spatangoids
Authors: Gage John
Published: May 2009

The life-histories of the erycinaceans Montacuta substriata and M. ferruginosa were investigated with special reference to the initiation of their ‘commensal’ associations. The planktotrophic larvae are released in summer as veligers after incubation within the adults, and they may spend several months in the plankton before settlement and metamorphosis. Larvae of both species, isolated from the Plymouth plankton, were reared to post-larval stages that were comparable with spat found associated with spatangoids. Some corrections are made of the identifications of planktonic larvae, of these and other Erycinacea, by previous authors. Experiments showed that, apart from being more active, the responses of walking post-larvae are similar to those I have described previously with adults. It is considered that the reactions operate, in an integrated manner similar to the adults, in initiating their associations with spatangoids; the behaviour of the adults in maintaining and re-establishing their associations would thus represent a retention of larval faculties. Possible reasons for the restriction of M. substriata to superficial burrowers and the less specific occurrences of small M. ferruginosa amongst spatangoids—including both deep and shallow-burrowing species—are discussed.
Respiration and feeding in some small copepods
Authors: Marshall S. M. , Orr A. P.
Published: May 2009

Observations were made on the feeding and respiration of the common small copepods in the Clyde sea-area, using cultures labelled with P for feeding experiments and the Winkler method of oxygen determination for respiration measurements.
Thalassomyces fagei, an ellobiopsid parasite of the euphausiid crustacean, Thysanoessa raschi
Authors: Mauchline J.
Published: May 2009

The development of an ellobiopsid parasite,Thalassomyces fagei (Boschma), within the cephalothorax of an euphausiid,Thysanoessa raschi (M. Sars), is described for the first time. The tissues of the young stages of the parasite have no intimate connexions with those of the host but become fused with them when the trophomeres begin to differentiate into a series of gonomeres. The parasites are found inT. raschi but have not been found in recent years in the associated population of the euphausiid,Meganyctiphanes norvegica (M. Sars), although it was recorded in one specimen of this species in 1925. The older stages of this parasite only occur inT. raschi in the Clyde during the period March-June but they have been recorded in the same species and other species of Northern Atlantic euphausiids in other sea areas later in the year. No fresh evidence has been found to decide whether these parasites have dinoflagellate, rhizopod, or fungal affinities.
A study of the seasonal changes of the water mass of Christchurch Harbour, England
Authors: Murray J. W.
Published: May 2009

Detailed sampling of the bottom water of Christchurch Harbour, England, was undertaken in conjunction with a study of the living and dead foraminiferids (to be described later). The Harbour is a shallow estuary with an unusual tidal regime of four high tides daily. During the winter the flow of fresh water from the rivers prevents sea water from entering much of the estuary. During the spring, summer and autumn, when drier conditions prevail on land, the sea enters the estuary as a salt wedge and there is pronounced salinity stratification. In addition to determinations of chlorinity, pH, dissolved oxygen and temperature, analyses of calcium were made during the spring, and of calcium and magnesium in the summer. It was found that calcium was preferentially removed from the bottom water, thus upsetting the calcium-chlorinity ratio. The cause of the calcium removal is thought to be biological activity. Magnesium was not affected by this process. A discussion of the results is presented and it is suggested that biological removal of calcium from the bottom water is particularly well developed in Christchurch Harbour owing to the extensive areas of shoal water favouring biological activity. Estuaries of this type may not be very common.
Physiological ecology of Patella. I. The effect of body size and temperature on metabolic rate
Authors: Spencer Davies P.
Published: May 2009

The metabolic or respiratory rate, measured as the aerobic oxygen uptake, of the limpets Patella vulgata L. and P. aspera Lamarck was determined over a range of temperatures in January and in July. In order to determine the effects upon metabolism of adaptation to habitat, P. vulgata living at high shore levels were compared with those living at low shore levels.

The respiratory rate is proportional to the power –0·3042 of the fresh body weight and the relationship is not affected by temperature or season, and is the same for both species.

There is very little difference in the rates of respiration of equal weight individuals of P. aspera and either group of P. vulgata in January. In July the respiratory rate of low-level P. vulgata and of P. aspera is higher than in January whilst that of the high-level P. vulgata is little changed.

The Q10 of respiration had a low value between the temperatures of 15–20° C in both species, and this is thought to represent a hitherto unrecognized form of acclimation to maintain metabolic constancy over the mean environmental temperature range. In P. vulgata low values of Q10 were correlated with high environmental temperatures. Lower Q10's were recorded in July than in January and, in addition, limpets which were adapted to the elevated temperature of high shore levels in July had lower Q10's than the limpets from low shore levels. This apparent acclimation of Q10 was not observed in P. aspera.

The significance of the differences in metabolic rate and in Q10 are discussed in relation to acclimation and its importance in the ecological distribution of the two species.
The carbon nutrition of some algae: the inability to utilize glycollic acid for growth
Authors: Droop M. R. , Mcgill Susanne
Published: May 2009

Thirty-nine strains of (mainly) supra-littoral algae were tested for their ability to utilize glycollic acid for chemotrophic and phototrophic growth at the' natural' pH of 8.c. In no instance was there convincing evidence that glycollate either supported growth in the dark or enhanced the growth rate in the light in the presence of carbon dioxide, although acetate performed one or both these functions in a number of the strains. It was concluded that glycollic acid was unlikely to serve as a significant carbon substrate in neutral or slightly alkaline habitats.
A survey of reflectivity in silvery teleosts
Authors: Denton E. J. , Nicol J. A. C.
Published: May 2009

A survey has been made of reflecting layers in the integument of selected fishes, including silvery sea lamprey and various silvery and partially translucent teleosts. Lamprey and juvenile rockling have only a stratum argenteum. Other silvery teleosts have a layer of oriented reflecting platelets lying outside the stratum argenteum; these lie more or less parallel to the vertical to the surface of the water.In dace, herring, and salmon parr the platelets on the upper flanks are tipped slightly upwards; but in some pelagic fishes, e.g. the mackerel and gar-fish, the platelets here are tipped downwards. Smelt, sand smelt, half-beaks, found in shallow or coastal waters, are partially translucent, partially silvery. The implications of these arrangements of reflecting layers are discussed. Both in clear oceanic waters, away from the surface, and in shallow or turbid rivers or ponds, light is distributed almost symmetrically about the vertical to the surface, and the greatest intensity is directed downwards. Under these conditions the reflecting layers diminish thevisibility of the fish from most fields of view because they reflect light approximately equal to the background light against which the fish is seen. On the lower flanks, when the surface is sloping, the reflected light tends to be spread and to beless intense than the incident light. Thin fishes, dark above with vertically reflecting sides, are effectively camouflaged except for the ventral extremity. The lower flanks of tapering or rounded fishes are well camouflaged by reflexion from below and behind because the platelets slope inwards towards the tail, and the projected area of incidence relative to reflexion is thereby increased.
On the buoyancy of the pearly nautilus
Authors: Denton E. J. , Gilpin-Brown J. B.
Published: May 2009

Nautilus macromphalus Sowerby when freshly caught was close to neutral buoyancy having a weight in sea water of about 0–2% of its weight in air. The animals without their shells varied considerably in density but the volume of the shell was an approximately constant fraction of the total volume of the whole animal and whole animals were brought approximately to the same density by havingmore or less liquid inside the chambers of the shell. About 80 % of the gas space in the shell was used to support the weight of the shell itself in sea water.In an adult animal the centre of buoyancy was found to be about 6 mm above the centre of gravity, which made the animal very stable in its natural swimming position, a couple of about 350 g. cm being required to turn it through 90°. The pearly partsof the chamber walls were impermeable to sea water but the chalky and horny siphuncular tubes joining the septal necks were very porous. The most newly formed tenor so chambers were the only ones to contain liquids in appreciable volume and theydid this in diminishing amounts from the newest to the oldest. The watery liquids found within the chambers were always hypotonic to sea water and sometimes markedly so; they contained principally sodium and chloride ions. One animal was in the process of forming a new chamber, this incomplete chamber was completely full of liquidwith an osmolarity close to that of sea water but differing in composition from seawater.
Some effects of salinity on the developing eggs and larvae of the plaice (Pleuronectes platessa)
Authors: Holliday F. G. T. , Jones M. Pattie
Published: May 2009

Eggs of plaice, Pleuronectes platessa L., were incubated in salinities of 5, 17.5, 35 and 50%. After fertilization a large concentration difference is maintained between the yolk and the external medium; this difference is present throughout development. The unfertilized egg becomes isosmotic with the medium within 24 h.

High mortalities were found at all stages of development in salinities below 17.5% most eggs died in the blastula or early gastrula stages. In addition, mechanical disturbance (e.g. during transport) also led to many deaths at this stage.

Water movement could occur between the environment and both the yolk and embryonic cells, it was detected by changes in the freezing-point of the yolk and changes in the volume of the blastula cells.

After hatching, the yolk-sac larvae tolerated salinities of 15–60% for 1 week, and the body fluid concentration was regulated within fairly narrow limits in these salinities. After metamorphosis, tolerance to high salinities was less (45% for 1 week), but tolerance and regulation in low salinities was greater (2.5% for 1 week). It is suggested that functional changes in the epidermis and kidney underlie these changes in tolerance.

Introduction

An investigation of the effects of salinity on the early development of the herring (Holliday & Jones, 1965) suggested that the ability to osmoregulate was present in the cells of the early blastula, but not in the vitelline membrane of the fertilized egg. The yolk was not fully regulated until gastrulation was complete; until this time it was approximately isosmotic with the medium in which it was being incubated.
Recent changes in abundance of intertidal barnacles in south-west England: a possible effect of climatic deterioration
Authors: Southward A. J.
Published: May 2009

Annual surveys carried out in south-west England since 1949 show that the arctic-boreal barnacle, Balanus balanoides, which was uncommon or rare in i960, has increased greatly in abundance during the colder years since then. Its numbers now approach those recorded in the 1930's, and there has been a corresponding reduction in abundance of the warm-water species, Chthamalus stellatus.
On the Nutrition and metabolism of zooplankton IV. The forms of nitrogen excreted ByCalanus
Authors: Corner E. D. S. , Newell B. S.
Published: May 2009

A study has been made of the nitrogenous compounds excreted byCalanus helgolandicus(Claus) collected at Plymouth.

Most of the excreted nitrogen is in the form of ammonia which accounts for 60–100% (average 74.3%) of the total, and some of the remainder may be lost as urea. There is no evidence for the excretion of measurable amounts of amino acids.

Whether the animals are starved or fed they are primarily ammonotelic, and the quantity of ammonia produced at 10° C (3.33 μg/g. dry body wt/day) is not significantly changed when the animals are used at an abnormally high experimental density. This latter condition does, however, lead to the production of large quantities of additional nitrogenous substances that give a positive reaction with ninhydrin.

Introduction

The amounts of nitrogen excreted by zooplankton have been measured by several workers. Harris (1959) used the method of Riley (1953) to estimate the copious quantities of ammonia produced by animals (mainlyAcartia tonsaandA. clausi) collected from Long Island Sound; Beers (1964), in laboratory experiments with the chaetognathSagitta hispida, estimated the excreted ammonia by the procedure of Kruse & Mellon (1952); and Corner, Cowey & Marshall (1965) determined the ammonia excreted byCalanus helgolandicusandC. finmarchicus, using a ninhydrin technique described by Moore & Stein (1954). The methods employed by Harris and by Beers are specific for ammonia: that used by Corneret al.estimates nitrogenous substances (e.g. amino acids) in addition to ammonia, but certain tests were made which seemed to exclude the possibility that these substances contributed significantly to the nitrogen excreted by the animals.
The defensive adaptations of Lima hians (Mollusca, Bivalvia)
Authors: Gilmour T. H. J.
Published: May 2009

The inability of Lima Mans Gmelin to enclose the soft tissues of the body within the shell is correlated with the development of other defensive adaptations.

L, Mans can automize entire pallial tentacles or parts of tentacles which subsequently secrete a viscous mucus distasteful to potential predators. Autotomy takes place at transverse septa along the length of the tentacles and mucus is secreted by epidermal gland cells.

The transverse septa of the tentacles also regulate the hydrostatic pressure of blood within the tentacles and permit the performance of complex locomotory movements. It is suggested that the septa were originally developed to serve this locomotory function and, secondarily, function as planes of weakness at which autotomy may take place.

L. Mans builds protective nests. The nests are constructed by burrowing into a gravel substratum and consolidating the walls of the burrow with byssal threads. When disturbed in the nest L. Mans performs locomotory movements which lead to enlargement of the nest. If the nest is broken the locomotory activities result in free swimming followed by attempts to burrow into the substratum to form a new nest. It is unlikely that L. Mans swims freely in nature except when displaced from the nest.

Introduction

Most bivalve molluscs react to unfavourable stimuli by retracting the soft parts of the body within the shell valves and contracting the adductor muscles to oppose the valve margins. In Lima hians Gmelin the mantle margin, even with its numerous long tentacles fully retracted, cannot be accommodated within the shell valves. In this paper the inability of L. hians to retract the soft parts within the valves is correlated with two types of defensive behaviour: (i) the secretion of mucus by the tentacles of the mantle margin and the autotomy of these tentacles, and (ii) the interrelated activities of swimming and nest-building.
Spatial, Temporal and Tidal Variation in Crab Populations in the Forth Estuary, Scotland
Authors: Mathieson S. , Berry A.J.
Published: May 2009

Five species of crabs were recorded in the Forth Estuary, of which Liocarcinus depurator and Cancer pagurus were confined to the lowest reaches where salinities are 24–35%‰. Carcinus maenas, Liocarcinus holsatus and Hyas araneus also occurred in the middle estuary where salinities are 22–31%‰ in summer but often fall to ~12%‰ in winter. A very few L. depurator and Cancer pagurus were confined to the lower estuary and mostly occurred in low tide trawls in summer. Carcinus maenas alone was recorded much further up the estuary where salinities rarely exceed 0–5·7%‰. Carcinus maenas predominated numerically throughout with an overall mean density of 0·0075 m−2 in the middle and lower estuary. Carcinus maenas in the estuary channel measured 16·6–82·9 mm carapace width (CW) with a modal size–class of 50–60 mm. Males were outnumbered by females (0·68:1 overall), and more markedly in summer than winter. Yet males were significantly bigger on average than females. Egg-masses were borne by 7·5% of all trawled females, but by 31·1% in April–May. On adjacent shores, by contrast, the much higher numbers of C. maenas were nearly all <20 mm CW. Low water trawls yielded significantly more C. maenas, but significantly lower proportions of males, than high water trawls. Liocarcinus holsatus was most abundant within the mid-lower estuary basin, with numbers decreasing both upstream and at the estuary mouth. Males outnumbered females by 2·26:1 overall, and most markedly at the extremities of the range. Males were significantly bigger than females, although sizes of both generally increased towards the mouth of the estuary. Only three of the 101 females bore eggs. Low water trawls yielded slightly more L. holsatus than high water trawls. Numbers of H. araneus increased markedly from mid-estuary to the estuary mouth where counts averaged 0·0021 m−2. Males outnumbered females by 2·17:1, and more so among those >40 mm CW. No female bore eggs. Records of the presence of C. maenas, Liocarcinus sp. and Hyas sp. all increased in the estuary from 1985 to 1995 reflecting increases in intertidal faunal diversity and changes in industrial practices since the early 1980s.
Reproductive Patterns and Tidal Effects on Spat Settlement of Mytilus Edulis Populations in Dundrum Bay, Northern Ireland
Authors: Snodden L.M. , Roberts D.
Published: May 2009

The gametogenic and spat settlement patterns of two Mytihis edulis beds were studied in Dundrum Inner Bay, Northern Ireland. There was evidence of gonad development throughout the year with the main development period between November and March. Spawning was protracted, lasting from May to November. Slight inter-annual and inter-population differences in the riming of the phases were observed but the cycles at both beds were broadly similar to each other and to those of other British and Irish sites. Settlement occurred throughout the year and there was evidence of both primary and secondary spat settlement at both sites. Although the reproductive cycles were similar, distinct seasonal and inter-site differences in spatfall were apparent. At the Downshire Bridge bed, settlement peaked during summer and was dominated by spat in the 0·;5-1·0 mm size range. At Ballykinler, settlement levels were highest in the winter months and larger (>1 mm) spat dominated the samples. The orientation of spat collection pads also significantly affected numbers of the larger (>1 mm) spat. Collectors facing the flood tide attracted significantly more secondary settlers than ebb-facing collectors. This effect varied seasonally and was greater at the Ballykinler bed. It is suggested that hydrodynamic regimes may be an important factor in the differences in settlement patterns of M. edulis.
Actinothoe Sphyrodeta(Cnidaria, Actiniaria): The First Records from Portugal and the Mediterranean Sea
Authors: Williams R.B.
Published: May 2009

The known geographical distribution of the sea anemoneActinothoe sphyrodeta(Gosse) (Cnidaria, Actiniaria), hitherto generally believed to occur in the north-eastern Atlantic Ocean from the Shetland Islands to the Bay of Biscay, has been extended with new records from the Iberian Peninsula. These records comprise three from the west coast of Portugal and one from the Mediterranean coast of Spain.

The sea anemones (Actiniaria) of the north-eastern Atlantic Ocean have been closely studied for at least a century and a half, and along with those of the Mediterranean Sea, constitute perhaps the best known actiniarian fauna in the world. Furthermore, there has long been discussion of the endemicity of Mediterranean sea anemones, and of apparent overlaps between the distributions of some Atlantic and Mediterranean species. It is, therefore, of particular interest when a species thought to have a solely Atlantic or solely Mediterranean distribution is discovered on the ‘wrong’ side of the Strait of Gibraltar. The anemoneActinothoe sphyrodeta(Gosse) was hitherto generally believed to occur only in north-western Europe, with a range from the Shetland Islands to the Bay of Biscay (e.g. Fischer, 1890; Manuel, 1981). It is reported here for the first time from Portugal and from the Mediterranean coast of Spain.
On the Density of Certain Amphipoda and Isopoda
Authors: Moore P.G. , Davenport J. , Middleton N.E.
Published: May 2009

Data are presented on the density of ten species of Amphipoda and two species of Isopoda from terrestrial to aquatic (freshwater through brackish water to marine) habitats, derived using a new modification of the displacement method involving batch testing of animals and subsequent Probit Analysis of data.

Surprisingly few data are available in the literature concerning the densities of marine organisms. Extensive work on this topic was published some half a century ago by A.G. Lowndes. He reported widely on crabs and lobsters (Lowndes, 1943a), echinoderms (Lowndes, 1953) and fishes (Lowndes, 1955). In his paper to the Linnean Society (Lowndes, 1938a) he included data on some of the smaller freshwater Crustacea. Gross & Raymont (1942) have published on the specific gravity of the marine copepodCalanus finmarchicus.

In espousing the displacement method for dealing with live individuals (Lowndes, 1938a,b, 1942, 1943b, 1955), he dismissed summarily earlier techniques that involved ascertaining whether killed or narcotized animals sank or floated in liquids of known density. While we recognize the limitations of the old methods, Lowndes’ displacement technique, although very accurate for individuals (he quoted figures to five decimal places), is very tedious to replicate [“elegant if somewhat exacting”, according to Hutchinson, 1967] and so reliance tends to be placed on figures obtained for very few individuals, typically only one or two. Even Lowndes himself was wary of attributing significance to the last two decimal places in his estimations, since individuals will vary in density according to sex, the contents of the gut etc. (Eyden, 1923; Lowndes, 1938b; but see Fox & Mitchell, 1953).