bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the nematocysts of Hydromedusae. III
Authors: Russell F. S. 
Published: May 2009

The nematocysts of five species of Anthomedusae, six species of Leptomedusae, and one Trachymedusa are described.In view of the additional support supplied by characters of its nematocysts it is suggested that the genus Chromatonema should be placed with Tiaranna in a new family, the Tiarannidae, in the Anthomedusae.Evidence on the possible evolution of microbasic euryteles from stenoteles is afforded by the nematocysts of Aglantha.
The occurrence of a marine leech, Abranchus blennii n.sp., resembling A. sexoculatus (Malm), in North Wales
Authors: Knight Jones E. W. 
Published: May 2009

Several specimens of an ichthyobdellid leech were found on Blennius pholis collected on the coast of Anglesey.The leech resembles Abranchus sexoculatus (Malm), a rare form only recorded previously from Sweden and not yet adequately described. Slight differences, however, indicate that it may be a distinct species and the name Abranchus blennii is provisionally put forward for it.A short review of the genus Abranchus and a description of the appearance and structure of the leech follow.My thanks are due to Prof. F. W. Rogers Brambell for his encouragement and advice; and to Mr W. H. Leigh-Sharpe for advice regarding the literature.
Zinc concentrations in juvenile flatfish
Authors: Milner N. J. 
Published: May 2009

In most demersal and some pelagic marine fish O- and I-group stages are found on inshore nursery grounds which are often situated in coastal indentations and estuarieswhere flushing rates are low and the build up of persistent pollutants can be correspondingly high. Their movements are restricted, only leaving the nursery areas towards the end of their second year (Lockwood, 1974; Riley, 1973). This, coupled with the fact that juveniles may be more susceptible than adults to pollutants, makes them particularly vulnerable to the potential hazards of inshore pollution.The physico-chemical properties of most trace metals, however, generally preclude their occurrence at high concentrations in sea water itself. Instead, most of the metal is transferred to the particulate phase of the water mass and to sedimentary reservoirs (Renfro, 1973) so that concentrations of metals in sea water very rarely reach levels which are known to be acutely toxic to fish. The main risk from direct effects of metals lies in poisoning resulting from internal accumulation.Little information is available on metal concentrations occurring in young fish. Hardisty et al. (1974) and Hardisty, Kartar & Sainsbury (1974) have examined zinc, cadmium and lead levels in O-group and older flounders from the Bristol Channel. Andersen, Dommasnes & Hesthagen (1973) found high concentrations of zinc in O- and I-group herring and sprat from Oslo Fjord, Cross & Brooks (1973) reported on manganese, iron and zinc concentrations in juvenile estuarine fish. Pentreath (1973 b) has reported on zinc concentrations in the organs of I-group plaice.
A scanning electron microscope study of notum structures in some dorid nudibranchs (Gastropoda: Opisthobranchia)
Authors: Kress Annetrudi 
Published: May 2009

Skin structures of nine different species of dorid nudibranchs were examined at the scanning electron microscope and the light microscope levels. From these observations the animals are grouped into three categories.1. Dorids with spicule-supported tubercles carrying a sensory knob (Rostanga rubra, Jorunna tomentosa, Onchidoris sparsa, Onchidoris pusilla).2. Dorids with small sensory papillae set in pits and distributed randomly between projecting spicules (Aegires punctilucens).3. Dorids with tubercles differing in shape from one species to another, invested with numerous spicules but without conspicuous sensory structures. The tips of the tubercles do, however, contain single sensory epithelium cells (Archidoris pseudoargus, Acanthodoris pilosa, Onchidoris muricata, Onchidoris bilamellata).
A comparison of traditional and novel ways of estimating growth rates from scales of natural populations of young bass (Dicentrarchus labrax)
Authors: Ottaway E. M. , Simkiss K. 
Published: May 2009

Traditional scale reading methods have been compared with [C]glycine uptake data to study scale growth in bass.Both methods are capable of being used to age young fish and determine their rate of growth. The glycine incorporation rate is, however, of more value in studying shortterm changes in fish growth. When applied in this way, it indicates that the apparent isometric relationship between scale and body length is actually the sum of a number of allometric interactions. Some of the errors that can occur in scale reading are demonstrated by the application of these methods.
Growth, Metamorphosis and Energy Conversion in the Larvae of the Prawn,Palaemon Serratus
Authors: Reeve M. R. 
Published: May 2009

The life-history of the larva of the prawnPalaemon serratus(Pennant) was studied in the laboratory and found to comprise a variable number of stages, dependent on feeding level and other factors. Larval moulting frequency was relatively constant at 3-day intervals, and could be followed in a population by daily examination for exuvia moult-casts. Length increase at each moult progressed arithmetically, and the highest mortalities occurred during metamorphosis. Consumption ofAnemianauplii by each larva rose from 30 to 400 per day. Populations of isolated animals (i.e. when cannibalism was excluded) were inspected daily and the exact number and duration of larval stages determined. Survival through metamorphosis was very high (over 85%) at both high and low feeding levels, although at the latter the larvae passed through more stages with more erratic duration times. At the end of the experiment, when all the larvae had metamorphosed, the mean dry weights at the high and low feeding levels were 7.7 and o.6 mg respectively. Larval stages could not be positively identified morphologically after stage III unless the history of the individual in question was known. It is suggested that the number of larval stages in the sea may also be very variable and difficult to determine.Energy-conversion efficiency was calculated from food uptake measurements and larval growth estimations, and was found to be 50–60% during most of the larval life, falling to 35% when the early post-larvae were taken into account.
A Short Investigation into the Habits, Abundance, and Species of Seals on the North Cornwall Coast
Authors: Steven G. A. 
Published: May 2009

1. In the course of three trips to the herring grounds in the vicinity of St. Ives five seals were sighted. Seven others were also seen at various other times and places in the course of five days spent in that locality.2. During a single night at sea in Port Isaac Bay eight seals were sighted.3. It was obvious from the movements of certain of the seals observed on the fishing grounds that they were attracted to the herring nets.4. Direct evidence that the seals actually remove fish from the nets was not obtained.5. Damage done to drift nets by seals is negligible.6. Grey Seals (Halichœrus grypus) are present in considerable numbers, and are probably the commonest seals in Cornish waters.7. Brown Seals (Phoca vitulina) appear to be few—they may even be rare—around Cornwall.8. There is at least one seal colony of considerable size in certain caves near Boscastle. This appears to consist of Grey Seals. Probably other such colonies exist on the Cornish coast.9. Clupeoid remains have been found in two out of the three Grey Seal stomachs which have been examined.10. Further and more exact knowledge of the habits and relative abundance of Grey and Brown Seals around the Cornish coast is desirable.
Development of Scolecolepis fuliginosa (Claparède)
Authors: Day J. H. 
Published: May 2009

1. The development of Scolecolepis fuliginosa (Claparède) is described from the egg to the young worm for the first time.2. Comparison of reared larvæ with larvse from the plankton did not reveal any important difference.3. The eggs are pelagic, and are similar to those of Nerine.4. A description is given of the histological structure of a ciliated pit which arises in early larval existence and disappears at metamorphosis. The structure of the glandular region of the pygidium is also described.5. It is apparent that from the attainment of the fourth setiger onwards, the centre of differentiation is located in the third setiger, so that segmental structures arise first in this segment and then appear in the first and second setigers as well as in the succeeding ones.6. The larva of Scolecolepis has three pairs of eyes, the third pair disappearing in the young worm long after metamorphosis is otherwise complete.
Studies in Sublittoral Ecology. I. A Submarine Gully in Wembury Bay, South Devon
Authors: Kitching J. A. , Machan T. T. , Gilson H. Cary 
Published: May 2009

1. A diving helmet can be used successfully on British coasts.2. An ecological survey, extending to a depth of 10 feet below low water of ordinary spring tides, has been made of a small area in Wembury Bay, S. Devon.3. Below low water of ordinary spring tides upward facing rock surfaces were occupied by a “Laminaria forest association.”4. Below L.W.O.S.T. vertical or overhanging rock surfaces were occupied by a “Distomus-Halichondria association.”5. Large brown Algæ are excluded from the Distomus-Halichondria association by some factor connected with the slope of the rock surface, other than inadequate illumination.6. Freedom from silt deposition may be responsible for many of the peculiarities of the Distomus-Halichondria association,—in particular for the importance of sponges, cœlenterates, and tunicates.7. Barnacles play an important part in the recolonisation of bare rock surfaces.
Measurement of Phytoplankton Population
Authors: Harvey H. W. 
Published: May 2009

A meter is described which measures the volume of water which has passed through a silk net which may be either towed or lowered and raised vertically.A double release gear and throttling arrangement allows the net to be opened and, later, closed at any desired depths.The catch of phytoplankton, from a volume of water which has been measured by the meter, may be assessed from its content of yellow-green pigments, which readily dissolve in acetone.A rapid method of measuring the pigment content of the catch in terms of arbitrary units of plant pigment is described. The arbitrary unit is related to numbers of two species of diatoms.The irregular distribution of phytoplankton in the sea is considered in connexion with representative sampling with this measuring net.
Annual Variation of Planktonic Vegetation, 1933
Authors: Harvey H. W. 
Published: May 2009

Vertical hauls were made with a very fine silk net having a meter attached, which measured the volume of water filtered, at positions off Plymouth throughout the year 1933.The quantity of phytoplankton was assessed from its content of yellowgreen colouring matter, and expressed in terms of “units of plant pigments” per cubic metre of water filtered.The diatom population per cubic metre at Station L4 on March 28th was estimated to contain phosphorus amounting to 2 mg. P2O5, whereas dissolved phosphate amounting to some 15 mg. P2O5 had been used from each cubic metre of water by the diatoms during the previous six weeks.It is concluded that the production of phytoplankton during this period greatly exceeded the quantity found at the height of the spring outburst, and that the excess had been eaten by the herbivorous zooplankton.
The auditory bullae–swimbladder system in late stage herring larvae
Authors: Blaxter J. H. S. , Denton E. J. , Gray J. A. B. 
Published: May 2009

Herring larvae, when they are about 30 mm long, swallow air and fill their auditory bullae with gas. It has been shown earlier that this is associated with a great increase in sensitivity to changes in hydrostatic pressure. Here we show that it is also associated with the appearance of a startle response to noises.At this stage of development, the utricular maculae are fully developed. However, the bullae are bounded by thin walls which are poorly calcified and the bulla membranes are thin and contain little elastic tissue. None the less the high-frequency cut-off in the mechanical responses to oscillating pressures is as high as that of the adult.
Geographical variations in the reproduction of the horse mussel,Modiolus modiolus(Mollusca: Bivalvia)
Authors: Brown R. A. 
Published: May 2009

The reproductive cycles of four widely separatedModiolus modioluspopulations from W. Sweden, W. and N. Norway, and Northern Ireland were examined in relation to their contrasting temperature regimes. Reproductive condition was analysed on the basis of the degree of development and numerical density of the gametes, and on size-frequency distributions of oocytes.All the Scandinavian populations had well defined spawnings, those of W. Sweden and W. Norway occurring in June and followed by a period of redevelopment and further gamete release. The N. Norway population spawned in July and subsequent redevelopment was not accompanied by further spawnings. Both Norwegian populations overwintered in a relatively ripe condition, but that from W. Sweden spent the winter in a low state of reproductive development. The N. Ireland population contrasted with the others in being continuously ripe and having no overt spawning, but rather a slow, constant release of gametes throughout the year.These differences are assessed in terms of the effects of the local temperature regimes on the interacting processes of gametogenesis and spawning. It is concluded that seasonal variability in temperature plays a major role in determining the extent and duration of gametogenesis, whilst spawning is more dependent upon the attainment of a limited range of minimum temperatures. The northern limit ofM. modiolusis therefore more likely to be determined by failure of conditions suitable for spawning and larval development than by a failure of gametogenesis.
On the Amount of Phosphoric Acid in the Sea-Water off Plymouth Sound. II
Authors: Matthews. Donald J. 
Published: May 2009

The amount of phosphoric acid in sea-water off Plymouth was at a maximum of 0.06 mg. per litre of P2O5 at the end of December, 1915, after which it fell irregularly to a minimum of less than 0.01 mg., which extended from the last week of April to the latter part of May; it then increased again and in January, 1917, reached the same value as the average for the first part of the month in the previous year.This seasonal variation is probably to be attributed to the removal of the phosphates from solution, at first by the fixed algæ, and later in the spring by the diatoms and for a short time by Phcœcyslis. There is also present in sea-water taken near Plymouth another soluble compound of phosphorus which can be converted into phosphoric acid by oxidising agents.
Growth Bands in the sea Urchin Echinus Esculentus: Results from Tetracycline-Mark/Recapture
Authors: Gage J. D. 
Published: May 2009

Recoveries of tetracycline-labelled specimens of the sea urchin Echinus esculentus (Echinodermata: Echinoidea) from a wild population marked two years previously indicate very low skeletal growth rates in large adults. The post-tag growth in the test of a smaller specimen showed two clear growth zones in the middle layer of the plates, this conforming to the expectation of a single growth band each year. Merging of the spinochrome pigment bands present in the outer layer near the plate edge in older urchins will probably result in underestimation of age based on counts of these bands.The large literature on growth banding in the European sea urchin Echinus esculentus L. and other echinoids is reviewed by Pearse & Pearse (1975), Smith (1980) and Gage (1991). Moore (1935) utilised spinochrome pigment banding in the genital (apical) plates of E. esculentus from the Isle of Man (Irish Sea) and Firth of Clyde (western Scotland) in one of the first studies utilising growth bands to interpret the age structure and growth rates of sea urchins. A single band was assumed to be formed each year. Counts of spinochrome bands have been used to obtain nearly all subsequently published age data for this species (Sime, 1982; Nichols et al., 1985; Sime & Cranmer, 1985; Comely & Ansell, 1988).The present study was aimed at helping to resolve differing interpretations of age and growth rates in Echinus esculentus provided by these studies. This was undertaken by time marking the skeletal plates of a large sample of a wild population accessible by scuba diving on a submerged rock reef at 10–15 m depth off the islet of Eilean Mor near the Dunstaffnage Laboratory.
An Epibiont on the Red-Water Ciliate Mesodinium Rubrum
Authors: Crawford David W. 
Published: May 2009

Spherical, opaque bodies (5–10 µm diameter) were frequently observed adhering to cells of the marine ciliate Mesodinium rubrum, particularly towards the end of red-water blooms in Southampton Water. Transmission electron microscope sections revealed these structures to be of biogenic origin, and packed with an amorphous, lipid-like material. No diagnostic features were observed to confirm their identity.The phototrophic ciliate Mesodinium rubrum (Lohmann) forms recurrent red-tides each summer and autumn in the Southampton Water estuary, UK (Williams, 1980; Soulsby et al., 1984). During a study of the impact of these blooms on the estuary, live cells were routinely observed microscopically. Frequently, but predominantly later in the bloom, numerous individuals posessed spherical, colourless, but opaque bodies, apparently attached or adherent to the outer cell membrane. Cells observed prior to the bloom, or at other times of the year, were never observed o possess such structures.Cells bearing these bodies were photographed live, or after preservation in Lugol's iodine, using the phase contrast optics of an Olympus BH2 photomicroscope.
The benthic environment of the North Sea (56° to 61°N)
Authors: Basford D. , Eleftheriou A. 
Published: May 2009

In an attempt to describe the physical and chemical characteristics of the sediments as an environment for the invertebrate benthos, a total of 273 stations covering the sector from 56° N to 61° N in the North Sea was sampled. The sediment samples which were collected by grab and corer were analysed for particle size (as well as silt-clay content and sorting), organic carbon, plant pigments and trace metals (Cd, Pb, Zn, Ni, Co, Cu). On a smaller scale a few stations were sampled for redox potential, pH and pesticides.Taking into account the geological history and the on-going hydrographic processes, explanations for the formation of the sedimentary provinces in the North Sea were provided. The sediments were predominantly fine to medium sand, but there was a depth-related gradient with the finer grades, organic carbon and, to a lesser extent, plant pigment being found in the deeper sedimentation basins of the Fladen Grounds and Norwegian Trench.Trace metals and pesticide contaminants associated with the finer organic and inorganic fractions were higher in the sediments of the above deeper areas as well as in the vicinity of estuaries. It could be concluded that despite the enhanced concentrations of Cd, Ni, Pb and Co, at the east of Shetland, which were due to a geochemical anomaly, there was no evidence of any important or large-scale contamination of the North Sea as a whole.
Some Anatomical and Physiological Differences in Chorda Filum from Coastal Waters of Finland and Great Britain
Authors: Russell G. 
Published: May 2009

A comparative study of Chorda filum populations from the British Isles (S 34‰) and the Baltic coast of Finland (S 6‰) has revealed differences in response by live adult thalli to treatment for 2 h with sea water of different salinities. Water uptake and loss by thalli differed significantly in salinities of х o‚ х 1/6, х ⅓ and х 1 ( = 34‰). British material showed severe cell disruption in freshwater whereas Finnish material did not. Killed thalli also behaved differently, British material showing little response to salinity treatment but Finnish plants continuing to react much as live tissues.Anatomical differences between populations were also observed, cortical cells in Finnish plants being significantly smaller than their British counterparts. Diaphragms traversing lumens of British material were simple, entire structures, but those in Finnish plants were deeply dissected and complex in organization.It is postulated that Baltic Chorda may have undergone a process of evolutionary divergence in response to its changed saline environment.INTRODUCTIONChorda filum (L.) Stackh. is one of several species of north Atlantic Phaeophyceae to be found in the inner Baltic Sea and Gulf of Bothnia; its geographical limit being associated with sea water salinity of approximately 4‰, (Waern, 1952; Hällfors et al. 1981). This species has been studied by Norton & South (1969) and South (1966) who traced the development of gametophytes and early sporophytes in culture media of different salinites. Although their cultures had been established from British material only, they felt able to argue from their results that the Baltic population did not constitute ‘… a different physiological strain specially adapted to the extreme environmental conditions prevailing there’.
The Right Hon. Thomas Henry Huxley
Authors: Lankester E. Ray 
Published: May 2009

The Journal of our Association cannot be allowed to appear without a few words in memory of our first President, the great naturalist and leader of Science, whom we all mourn.Huxley's studies in marine biology, and his position as a Government official, as well as his keen, practical common-sense, made his selection as a member of two Government Commissions on Fisheries (in 1863 and again in 1883) very appropriate. He did valuable work on those Commissions, and in 1881 was appointed, by Sir William Harcourt, to be Inspector of Salmon Fisheries. In 1883 he took an active part in the work of the International Fisheries Exhibition, and emphasized in an address given there, the fact that, whilst civilized man had brought all the resources of science to bear on the “harvest of the land,” little or nothing had been done in the same spirit for the “harvest of the sea.”
The Vertical Distribution of Marine Macroplankton. X. Notes on the Behaviour of Sagitta in the Plymouth Area
Authors: Russell F. S. 
Published: May 2009

1. The diurnal behaviour of Sagitta of different sizes is shown as a result of collections made with the 2-metre stramin ring-trawl throughout 24 hours on July 15th–16th, 1924, and on June 3rd–4th, 1926.2. The younger stages ofSagitta elegansappear to withstand higher intensities of light in the daytime than do the older stages, and they migrate first to the surface at dusk, as do those ofSagitta setosa. The older stages leave the surface first at dawn.3. Diagrams are given showing the curves of equal intensities of light beneath the sea surface throughout 24 hours as calculated from air intensities obtained in June, with a reflection loss of 15%; (a) assuming a coefficient of absorption of 0·200 at all depths, and (b) assuming a coefficient of absorption of 0·100 at all depths.4. It appears, from a comparison of the behaviour ofSagitta eleganswith the calculated light conditions beneath the surface, that the older Sagitta at any rate are more sensitive to light in the early morning after the darkness of the night and can become adapted to light of higher intensities later in the day.5. Previously published observations on the behaviour of Sagitta sp. on June 17th–18th–19th, 1925, show quite a different type of behaviour from the above, possibly due to more transparent water, the Sagitta only appearing abundantly above 30 metres in the dark. They had again migrated to below 30 m. before there was any appreciable light.