bluuebunny/crossref_metadata_2025 huggingface dataset:
The Use of Cuprous Oxide and other Rectifier Photo Cells in Submarine Photometry
Authors: Atkins W. R. G. , Poole H. H.
Published: May 2009

1. Photo-electric cells of the rectifier type are useful for approximate measurements of light intensity, in air or under water, using a lowresistance galvanometer, the current through which may be reduced by a special shunt keeping the circuit resistance constant.

2. Such an arrangement has proved serviceable for shore work, a light gun-metal photometer, housing a cuprous oxide cell, having been carried about by a diver.

3. These rectifier cells can also be used at sea, but instead of the current, the E.M.F. is determined by means of the potentiometer outfit as used at sea in previous years.
On the Biology of Calanus finmarchicus. II. Seasonal Variations in the size of Calanus finmarchicus in the Clyde Sea-Area
Authors: Marshall S. M.
Published: May 2009

The size of the cephalothorax in Stage IV, Stage V, and Stage VI Calanus has been measured during the year 1931–1932 at three stations in the Clyde Sea-Area.

In general the size was greatest when the water temperature was low, and least when it was high, but besides this there was a series of increases and decreases in size which were apparently connected with the breeding periods. The Calanus produced at the beginning of a breeding period were large (at Station I) and those produced at the end were small (at Stations I and II). The greatest production of eggs usually occurred when the female Calanus were of small size.

During the autumn of 1931 the Stage V Calanus from Station IV (upper Loch Fyne) were considerably larger than those from the rest of the area, but this distinction had been lost by the autumn of 1931.

Stages IV and V Calanus taken in the top 30 m. were almost invariably smaller than those from deeper water.

The Calanus show a very wide range of sizes, the range for Stage V overlapping those for both male and female. Possible causes of this are discussed.
Contributions to the Biology of the Mackerel, Scomber Scombrus L.: Mackerel Migrations in the English Channel and Celtic Sea
Authors: Steven G. A.
Published: May 2009

In the English Channel and Celtic Sea mackerel spend the winter months on the sea floor densely packed in places where its level is interrupted by banks and gulleys.

In the early spring the fish rise to the surface and migrate to a common spawning ground that lies far out to the westward of the Scilly Islands in the vicinity of the 100-fathom contour.

The very localized positions in which mackerel spend the winter are widely distributed throughout the area in both deep and shallow water. Large schools of migrating fish converge upon the spawning ground from many directions, therefore, in the spring for spawning.

Fish that have wintered near the land must migrate offshore to reach the spawning ground; those that spend the winter on the bottom to seaward of the spawning ground must migrate shorewards to reach it. Off the south-west of England there is no single shoreward migration to spawn in shallow water as has previously been thought.

In the North Sea the chief spawning grounds of the mackerel are also near the 100-fathom contour which, in that region, happens to lie very close to the land in the Skagerrak and along the Norwegian coast. The chief spawning migration of the North Sea mackerel is therefore towards the coast from offshore localities.

This migration is, at the same time, chiefly from shallow to deeper water.

Existing information concerning the mackerel populations on the westernside of the North Atlantic points to the probability that their spawning habits and migratory movements do not differ greatly from those of the mackerel in North European waters.
A Contribution to Our Knowledge of the Life History of Arenicola Marina L.
Authors: Newell G. E.
Published: May 2009

The breeding season of the lugworms of the Whitstable area is a sharply defined one, extending for 14 days between the new moon and full moon spring tides in the second half of October. Spawning begins slowly and reaches a maximum at the intervening neap tides and then declines in intensity.

Both eggs and sperms are discharged from the burrows at extreme low water to lie on the surface of the sand. Here fertilization occurs.

No germ cells were detected in the body cavity from November to June, but from August onwards to the end of October 98% of the adult worms are ripe.

At the end of the spawning period about 40% of the adults die.

A brief description of gametogenesis and of the mature gametes is given.

Germ cells are discharged through the nephridia.
Cleansing Mechanisms and the Function of the Fourth Pallial Aperture inSpisula Subtruncata(Da Costa) andLutraria Lutraria(L.)
Authors: Yonge C. M.
Published: May 2009

Spisula subtruncatais a shallow-burrowing member of the Mactridae which inhabits silty sand. Adaptations to such conditions include long frontal cilia on the gills (Atkins), and the presence of a siphonal membrane with associated mantle folds over-arching a waste canal, as postulated by Kellogg for allied species.

The mantle edges are free ventrally, but are normally closely applied except for a short distance at the base of the inhalant siphon, an effective fourth pallial aperture being so formed. Through this opening material from the waste canal is ejected.

Lutraria lutrariais a deep-burrowing species belonging to the same family. The general resemblance toMya arenariais due to convergence. Cleansing currents resemble those ofSpisula subtruncataand there is a similar waste canal, but the siphonal membrane and the long frontal cilia associated with a silty environment are absent.
The Gonads, Larvae, and Budding of the Polystyelid Ascidians Stolonica and Distomus
Authors: Berrill N. J.
Published: May 2009

Stolonica socialis (Hartmeyer) and Distomus variolosus Gaertner are two species of styelid ascidians with a capacity for budding and colony formation, found on both sides of the western end of the English Channel. Distomusoccurs immediately below the level of extreme low spring tides, commonly encrusting the sides of rocks and laminarian bases. Stolonica is more usually found by dredging in deeper water, on the upper sides of stones or gravel bottom. Their external appearance and general internal anatomy have been well described and beautifully illustrated in the monograph of Lacaze-Duthiers and Delage (1892), while the process of budding has been investigated by Selys-Longchamps (1917).
On the Seasonal Abundance of Young Fish. IX. The Year 1947
Authors: Corbin P. G.
Published: May 2009

The 1947 records of the seasonal abundance of the pelagic young stages of teleosteans in the plankton of Plymouth off-shore waters are a continuation of the series of observations made by Mr F. S. Russell (1930–47). The form of the previous reports is retained. The dates on which collections were made are given in Table I, and the monthly average catches of young fish in Table II. The fortnightly averages of all young fish less clupeids are shown in Fig. I, together with the corresponding curve for the period 1930–34.
The Relation of the Substratum to the Metamorphosis of Ophelia Larvae
Authors: Wilson Douglas P.
Published: May 2009

Experiments with larvae of Ophelia bicornis Savigny have shown that they metamorphose most readily in sand from their natural habitat and with hesitancy or not at all in sands from other sources. Their natural sand consists largely of smooth rounded grains of quartz, very uniform in size; sands of
smaller and more angular grains are unfavourable to settlement and metamorphosis. It appears that size and shape of the sand grains, or perhaps, more likely, the sizes and shapes of the interstices among the grains, perceived probably by the tactile sense, is the main stimulus to metamorphosis. Chemical substances dissolving out of the sands do not seem to be responsible for this.

There is a period of time, amounting under favourable conditions to several weeks, during which an Ophelia larva is able to settle and metamorphose as soon as it comes into contact with a substratum suitable for adult life.

The ability of the larvae to distinguish bottom deposits suitable for adult life from those which are unsuitable must be of great advantage to the species in maintaining normal distribution and in conserving larvae.
The cycle of phosphorus in the waters of the English Channel
Authors: Armstrong F. A. J. , Harvey H. W.
Published: May 2009

Determinations of total phosphorus in water samples have shown areas in the western English Channel with water containing as little as 10 mg. P/m.3, and other areas with double, and more than double, this concentration.

The integral mean concentration of total P in the water column, 20 miles off-shore from Plymouth, has fluctuated between 10 and 16 mg. P/m.3 since June 1947.

The changes which have taken place in this integral mean concentration are attributed to different water masses, of different total phosphorus concentration, passing through the area, rather than to a seasonal change in the total phosphorus content of a water mass. No marked deposition of phosphorus-containing detritus could be found.

Changes in this integral mean were not coincident with changes in salinity. The geographical distribution of total phosphorus does not coincide with the geographical distribution of salinity.
Algal records for the Plymouth region
Authors: Parke Mary
Published: May 2009

The greater number of the species given in this list are new records for the Plymouth region. Recent records for some rare species have also been included.
The determination of ammonia in sea water
Authors: Newell B. S.
Published: May 2009

A sensitive, specific and precise method for the determination of ammonia in sea water is presented. The method depends upon the oxidation of ammonia by chloramine-T and subsequent coupling with phenol to produce indophenol blue in an n-hexanol extract. Molar absorption coefficient ca 84,000. Values of ammonia measured in samples from the English Channel are given and the effect of freezing on samples for ammonia analysis is discussed.
Occurrence of the entocommensal rhynchocoelan, Malacobdella grossa, in the oval piddock, Zirfaea crispata, on the Yorkshire coast
Authors: Gibson Ray
Published: May 2009

Various aspects have been studied of the relationship between the entocommensal nemertean Malacobdella grossa [O.F. Müller, 1776] and its host on the Yorkshire coast, the lamellibranch Zirfaea crispata L. Larger host populations clearly show both a higher overall percentage infection and greater numbers of multiple infections. Larger hosts tend to harbour larger Malacobdella; allied with this fact is the conclusion that the older the host population the more restricted is the availability of potential hosts for future infections.
Plastron respiration in the marine fly Canace
Authors: Hinton H. E.
Published: May 2009

The larva of the fly Canace nasica Haliday feeds on Enteromorpha in the intertidal zone. Its pupae, like those of a number of other intertidal flies, have plastron-bearing spiracular gills. The gills are unlike those of any other known Diptera in that they are modified spiracles: those of other flies are modifications of the body wall adjoining the spiracle, or of both the body wall and the spiracle. Although the spiracular gills are pupal structures, they are the respiratory organs of the adult before it emerges from the puparium.
A calycopsid medusa from the Firth of Clyde
Authors: Edwards C.
Published: May 2009

Anthomedusae of the family Calycopsidae are in general oceanic in distribution. The only species recorded from British waters isBythotiara murrayiGünther, reported from fairly deep water far offshore from the west and southwest coasts of Ireland. Its early stages have been unknown. A very young medusa caught at the surface in the Firth of Clyde has been reared through several stages, which are described and figured. It is considered to be a young B.murrayi.
The biology of Schistomysis spiritus [Crustacea, Mysidacea]
Authors: Mauchline J.
Published: May 2009

Schistomysis spiritus (Norman) breeds throughout the year in the Clyde and in Loch Ewe, Wester Ross, but breeding is more intense at some seasons than others. The over-wintering population in the Clyde breeds in March/April, the progeny growing and becoming sexually mature in July/August to produce a further generation which matures and breeds in October/November. In Loch Ewe the over-wintering population breeds in February, March and April and members of this spring generation begin breeding in May and continue to breed until September; the number of S. spiritus breeding in Loch Ewe decreases sharply after September and no autumnal peak of breeding, such as that in the Clyde, was found during the period investigated. The number of young carried in the marsupium varies seasonally, being 20–30 in May/June and 2–6 in midwinter. The food and the horizontal and vertical diurnal and seasonal movements of this species are discussed.
Receptor organs in the coxal region ofPalinurus vulgaris
Authors: Alexandrowicz J. S.
Published: May 2009

In the coxal region ofPalinurus vulgarisLatr. the following proprioceptors are present: (1) a thoracico-coxal muscular receptor, (2) two innervated elastic strands (depressor and levator receptors), and (3) a coxo-basipodite receptor. Thus,Palinurushas the same number of these organs as some Brachyura and Anomura, but differs fromHomarusandAstacus, which have five of them.

In all the five thoracic segments carrying the legs the receptor organs inPalinurusoriginate on special receptor rods which are thin projections of the endophragmal skeleton.

The muscle elements of the muscular receptor are surrounded by connective tissue which in the proximal part of the muscle forms a thick sheath. To the receptor rod the muscle is attached by a short tendon. The motor fibres reach the receptor muscle at about the midpoint of its course.
Basal sand and gravel patches with separate indications of tidal current and storm-wave paths, near Plymouth
Authors: Flemming N. C. , Stride A. H.
Published: May 2009

Diving observations and more wide-spread coverage by Asdic show that the late Holocene basal neritic deposits of the broad bay between The Lizard and Start Point are represented by three main facies whose character depends on the two bed-transport paths converging there. The sheet sands laid at the end of the path with a good supply show a progressive geographical change in texture. On the other path, where sand is in short supply, there are elongated patches of somewhat coarser, well-sorted sand with ‘silt’ balls, alternating with shell-rich gravel patches. While the sand patches are laid out along the path of the strongest tidal currents, the ripple marks of the gravel can only be constructed by long waves from the Atlantic.
The hydroid Trichydra pudica and its medusa Pochella polynema
Authors: Edwards C.
Published: May 2009

The systematic position of the hydroid Trichydra pudica has been uncertain because of lack of knowledge of its life-history. Medusae released from it have been reared to maturity and prove to be the species Pochella polynema. The stages of development of the medusa are described and figured. The systematic relationships of the medusa are discussed: it has the general characters of the Anthomedusae, to which the species is accordingly removed. The name Trichydra pudica has priority and should be used for both hydroid and medusa. The apparently related species Pochella oligonema should be known as Trichydra oligonema.
The accumulation from water of65Zn,54Mn,58Co and59Fe by the mussel,Mytilus edulis
Authors: Pentreath R. J.
Published: May 2009

The accumulation from sea water of65Zn,54Mn,59Fe and58Co by the mussel, Mytilus edulis, has been studied in relation to the stable element levels of these isotopes both in the sea water and in individual tissues. For all four radionuclides the greatest accumulation occurred in the stomach and digestive gland samples and further localization of65Zn and69Fe was demonstrated by autoradiography. As the animals were starved during the accumulation period the loss of stable elements by individual tissues was also followed. Again the most notable effect occurred in the digestive gland tissues with the exception of a large loss of iron by the foot. Autoradiography showed that after two weeks accumulation59Fe occurs in large clusters in the foot, notable in the byssus gland area. These clusters disappear after a further two week period and may thus be secreted into new byssus threads.
Factors controlling the availability of sediment-bound lead to the estuarine bivalve scrobicularia plana
Authors: Luoma Samuel N. , Bryan G. W.
Published: May 2009

Concentrations of lead in the soft tissues of the deposit-feeding bivalve Scrobicularia plana have been compared with the physicochemical characteristics of sediments in 20 estuaries in southern and western England and one in north-west France. The results indicate that the biological availability of lead in the sediment is controlled mainly by the concentration of iron, and that the concentration of lead in the bivalve may be predicted from the Pb/Fe ratio in 1 N hydrochloric acid extracts of surface sediments.
Gill structure in the common limpetPatella vulgata
Authors: Nuwayhid M. A. , Davies P. Spencer , Elder H. Y.
Published: May 2009

The gills ofPatellaconsist of a row of triangular shaped leaflets suspended from the roof of the pallial groove. The surface of each gill is thrown into a series of transverse furrows. Tufts of cilia are irregularly distributed over the surface and generate a current of water which flows in the opposite direction to the flow of blood within. The central part of the gill comprises a large haemocoelic space traversed by trabeculae which contain muscle fibres and suggesting that the flow of blood through the gill may be under nervous control. A blood channel runs around the periphery of the gill.

The epithelial layer bounding the blood space comprises a single layer of columnar epithelial cells. The outer surface is protected by a structured mucopolysaccharide glycocalyx held in place by a dense mat of microvilli. The cells contain clearly defined mitochondria, Golgi complex, lysosomes, rough and smooth endoplasmic reticulum. In addition, the non-ciliated cells are characterized by a layer of membrane-bound granules, of unknown function, in the apical cytoplasm.

Phagocytes are frequently found associated with the basement membrane. They contain large membrane-bound granules and appear to move outwards between the epithelial cells to expel the granules at the outer surface of the gill. It is possible that the gill has an excretory as well as respiratory role in the physiology of the animal.
Development, location and relocation of sensory and neurosecretory sites in the eyestalks during the larval and postlarval life of Palaemon serratus (Pennant)
Authors: Bellon-Humbert Ch. , Thijssen M. J. P. , van Herp F.
Published: May 2009

Ontogenesis of the eyestalk structures in Palaemon serratus has been studied during the larval and postlarval life by means of scanning electron microscopy (SEM) and light microscopy (LM). At hatching, a larval sensory pore is observed in the zoea. The organ of Bellonci is present with its typical onion bodies. During larval life, this organ grows and differentiates. Vacuolization in the organ of Bellonci starts in stage 4. At the same time, the giant neuron appears, but the sinus gland cannot be recognized before stage 5.

During larval life, vesicular cells are present in the optic medullae with an increase during stages 4 and 5. The differentiation of the neurosecretory cells of MEX (medulla externa X-organ) and MTGX (medulla terminalis ganglionaris X-organ) occurs with metamorphosis. The main sensory pore appears with metamorphosis and becomes clearly visible in postlarval life.

The movements of the structures, which occupy different positions in larvae and adults, are described in relation to the longitudinal axis of the eyestalk. A schematic representation explains the torsion of the eyestalk and the dynamics and growth during the formation of the eyestalk structures.
Monthly-mean residual flows through the Dover Strait, 1949–1972
Authors: Prandle D.
Published: May 2009

An estimate is made of the mean value of residual flow through the Dover Strait for each month over the 24–year period from 1949 to 1972. The estimates are based on results from a modelling investigation by Prandle (1978) where it was shown that the residual flow consists of three components, (a) a tidal residual, (b), a wind-driven residual and (c) a flow due to a long-term gradient in mean sea level. The components (a) and (c) are assumed to be constant and the value of (b) is deduced using wind data recorded by Dutch Light Vessels located in the southern North Sea.

The mean flow over the whole period amounts to 155 × 103 m3 s–1 into the North Sea with a maximum value of 364 x 103 m3 s–1 and a minimum of – 15 × 103 m3 s–1 (out of the North Sea). One notable feature of the complete time series is the surprisingly small variation in the annual mean flows; perhaps this stability in the annual flow is of significance to the marine biology of the area.

The validity of the computed time series is established by reference to comparable data including a 9–year record, from cross-channel submarine cables, of the potential induced by the flow of water through the Earth's magnetic field. Additional comparisons are also made with the results of a previous study of daily-mean flows.
A versatile tide machine and associated activity recorder
Authors: Graham J. M. , Bowers R. , Gibson R. N.
Published: May 2009

The paper describes the design and use of a tide machine capable of producing near-sinusoidal hydrostatic pressure cycles varying in period from 12 to 999 min and in amplitude from 0·4 to 3·2 m. In conjunction with infra-red detection units and a microprocessor logging system the apparatus can be used to detect and record the response of a variety of organisms to cyclic pressure changes.
A comparative study of the anatomy of the oncomiracidia of the hexabothriid monogeneans Rajonchocotyle emarginata and Hexabothrium appendiculatum
Authors: Whittington I. D.
Published: May 2009

Previous studies of the anatomy of the oncomiracidia of the hexabothriids Rajonchocotyle emarginata and Hexabothrium appendiculatum have been made on unhatched larvae viewed through the egg shell or on larvae pushed out of the egg by coverslip pressure. A study of freshly hatched, free-swimming oncomiracidia has permitted a more detailed anatomical study especially of the gland cell system, the distribution of locomotory ciliated cells and surface sensilla and the flame cell system. Anatomically, the two larvae are closely similar but the oncomiracidium of R. emarginata possesses spherical refringent droplets in the locomotory ciliated cells and, in the head region, a pair of translucent bodies which may be photoreceptors. The oncomiracidia of both parasites possess posterior body gland cells with ducts entering the haptor. Such gland cells have not been recorded previously in the larvae of hexabothriids or in those of other polyopisthocotyleans and the function of these and other gland cells is discussed.
Studies on the behaviour of the oncomiracidia of the monogenean parasitesHexabothrium appendiculatumandLeptocotyle minorfrom the common dogfish,Scyliorhinus canicula
Authors: Whittington I. D.
Published: May 2009

The gill-parasitic polyopisthocotylean monogenean,Hexabothrium appendiculatumand the skin-parasitic microbothriid monogenean,Leptocotyle minorshare the same host, the common dogfishScyliorhinus canicula. The larvae of these parasites are stimulated to hatch by host skin secretions and the behaviour patterns of these larvae have been found to be remarkably similar. The freshly hatched oncomiracidia of both parasites rarely remain swimming (in the presence of hatching stimulants) for more than 30 min; there is a strong tendency for the larvae to attach themselves temporarily or permanently by either the anterior or posterior ends to glass or Perspex surfaces. Other important features of the behaviour of these oncomiracidia are their erratic mode of swimming and their apparent lack of response to environmental stimuli such as light, shadows, mechanical disturbance or water currents. There is some evidence that the swimming oncomiracidia of both parasites may be negatively geotactic after hatching but this response is weak and of short duration. The erratic swimming pattern, the lack of response to environmental factors and the readiness to attach to available surfaces seem likely to be particularly favourable for the establishment of larvae on the surfaces of dogfishes foraging at the sea bottom and providing the hatching stimulus for drifting eggs.
The nauplii of Balanus balanoides (Cirripedia:Thoracica) taken in January and February in Northumberland waters
Authors: Evans F. , Burrows M. T.
Published: May 2009

Stage-2 nauplii larvae were taken in near-surface inshore tow-nets on the Northumberland coast in January and February of 1986, confirming isolated reports of similar observations in 1979–80. These occurrences are much earlier than expected from the normally described progression of naupliar release in British waters. It is suggested that premature larval release may be occasioned by damage to, or predation on, parent colonies.
Comparisons of herring behaviour in the light and dark: changes in activity and responses to sound
Authors: Blaxter J. H. S. , Batty R. S.
Published: May 2009

Comparisons of the behaviour of herring (Clupea harengusL.) were made in the light and dark by means of an infra-red sensitive TV system and video recording. Herring which were schooling in the light became less active in the dark, their swimming speed decreased, they tended to disperse and the proportion of gliding compared with swimming fish increased. Herring which were not schooling in the light increased their swimming speed in the dark.

When subjected to transient sound stimuli herring made fast-startle responses. The proportion of fish responding was lower in the dark. The directionality of the response (the proportion turning away from the sound source) was the same in the light and dark suggesting there was no visual component in the response.

The proportion of swimming and gliding fish affected both response rate and directionality. Gliding fish tended to have a higher response rate and better directionality than swimming fish, although this depended on the conditions of the experiment. The configuration of the body of swimming fish at the onset of a transient sound stimulus was important. Of the swimming fish, over 80% of the responders turned away from the direction in which the tip of the caudal fin was pointing at the onset of the stimulus. Gliding fish are in a better ‘neutral’ posture to initiate a startle response and to turn away from the sound source.

Comparisons of awareness (sensory thresholds) in the light and dark using startle responses are complicated by differences in the numbers of gliding and swimming fish.
Behavioural, physiological and morphological adaptations of the shanny (Blennius pholis) to the intertidal habitat
Authors: Laming P. R. , Funston C. W. , Roberts D. , Armstrong M. J.
Published: May 2009

Immersed shannies (Blennius pholis) showed peak locomotory activity coincident with daylight high tides. Emersion caused cessation of breathing and bradycardia though Q02was little affected. Q02fell, however, when the abdomen was enclosed in an impermeable sheath to block cutaneous respiration. Gulping of air into the extensively vascular oesophagus probably also acts as a means of aerial respiration. Reimmersion of fish caused a transient bradycardia followed by a tachycardia and a fall in Q02followed subsequently by a rise. The results are discussed in relation to the behavioural, circulatory, respiratory and morphological adaptations of the shanny to the intertidal habitat.
Light and nutrient status of algal cells
Authors: Droop M. R. , Mickelson M. J. , Scott J. M. , Turner M. F.
Published: May 2009

Chemostats were used to construct nutrient (vitamin B12) and energy budgets for the flagellateMonochrysis(Pavlova lutheri(Droop) Green) under varying conditions of nutrient and light limitation and luxury, the aim being to describe light limitation and luxury in terms analogous to those of the Cell Quota nutrient model. Measurements were made of steady-state dilution rate, biomass, cell quota, cell chlorophylla, cell energy content, dark respiration and photosynthetic efficiency, under low irradiance (<13 W per m2).

Cell energy content was 0·54 joules per million cells and was not influenced by growth rate or nutrient/light status. Cell chlorophyllawas 25% less in the nutrient-limited cultures and did not show a clear trend with growth rate except in cultures receiving less than 4·3 W per m2. The effective specific extinction coefficient was 0·12 cm2perμg chlorophyll. The photosynthesis/irradiance relation was linear. The mean slope (= efficiency) in samples from the light-limited chemostats was 0·225 and was independent of dilution rate. Samples from nutrient-limited chemostats showed a much lower slope, which decreased with decreasing dilution rate. These findings were confirmed by the chemostat kinetic data. Dark respiration varied with dilution rate in a hyperbolic manner and was greater in the nutrient- than the light-limited chemostat.

Light level had no effect on the subsistence quota when the nutrient was limiting, whereas under light-limiting conditions the subsistence quotas were enlarged in inverse proportion to the incident irradiance, thus showing a threshold rather than multiplicative interaction between light and the nutrient.

Energy absorption was very little reduced on nutrient limitation, the great reduction in overall efficiency being associated mainly with the reduction in photosynthetic efficiency.

The reciprocal of photosynthetic efficiency was shown to be analogous to a standardized nutrient cell quota, and an analogous coefficient of luxury could be defined as the ratio of the light-limited to nutrient-limited photosynthetic efficiency at the same growth rate. Thus, light limitation and luxury could be described in terms compatible with the nutrient model without having to introduce new concepts, and a practical criterion between light- and nutrient-limitation could be provided.
The biology of Barleeia unifasciata (Gastropoda:Prosobranchia) in red algal turfs in S.W. Ireland
Authors: Southgate T.
Published: May 2009

Variation in the abundance of Barleeia unifasciata is compared in several red algal species between June 1978 and June 1980 at Cooskeen Cove, Bantry Bay, Ireland. Population abundance in all algae varied seasonally, exhibiting a cycle of late-summer to autumn maxima, with winter to early summer minima. Greatest abundance was recorded in those algae which formed compact turf-like growths suitable for the entrapment of diatoms and detrital material and provided greatest shelter from wave-crash. Length frequency data showed the main recruitment period to be late June-October with a peak in August with juveniles present in all months of the year. Maximum life span was shown to be 2 years or more with only 15 % of the population surviving into the second year. Sexual development and reproductive cycle was determined for 0 + and 1 + animals. Mature males produced sperm continuously throughout the year. Not all 0 + females spawned in their first year. Summer spawning 0 + females exhibited reduced sexual activity in October and spawned again in the following summer. Some 1 + females spawned in winter and spring. Delayed sexual development in some individuals of both sexes was related to late hatching.
Chamber refilling in Nautilus
Authors: Ward Peter D. , Greenwald Lewis
Published: May 2009

Freshly captured Nautilus macromphalus were observed to place new cameral liquid into emptied or partially emptied chambers, both at the surface and at 250 m, in response to sudden buoyancy increase. The sudden addition of buoyancy was accomplished either through removal of cameral liquid from chambers, removal of shell material from the apertural region of the body chamber, or by cementing buoyant corks on the sides of the shell. A maximal refilling rate of 100 μl/h was observed. The osmolality of refilled cameral liquid was observed to match closely the osmolality of the original cameral liquid. The refilling mechanism allows Nautilus to regain neutral buoyancy after sudden buoyancy gain, such as could be expected to occur from shell loss due to predatory attack on the Nautilus, or from shell breakage.
Growth of the edible crab (Cancer pagurusL.) off south-west England
Authors: Bennett D. B.
Published: May 2009

Moult increments, annual moult frequency and hence annual growth were determined from suture-tagged edible crabs (Cancer pagurusL.) released and recaptured off Devon, Cornwall, and Dorset.

The average moult increments of males and females at a premoult carapace width of 100 mm were similar; at larger sizes the average moult increment of females was considerably less than that of males. Annual moult frequency ofC. pagurusin south-west England decreased with increase in size, females more so than males.

As a result of the smaller moult increments and lower moult frequency of females, their annual growth is considerably less than that of males. This appears to be the result of three aspects of sex and reproduction: (1) reduction in moult increments, probably as a result of competition for nutritive resources between egg production and body growth; (2) the interruption of the moulting cycle by successive annual spawnings from a single impregnation at the previous moult; and (3) accentuation of the larger increments in weight at moulting of male crabs due to the allometric growth of their chelae. A consequence of the higher growth rate of males is the presence of very large male crabs – a distinctive feature of the population structure of the stock off south-west England.

The growth of C.pagurusin south-west England was compared with published data for stocks off the east and north-east coast. Moult increments were similar for both areas, but there were considerable differences in the moult frequencies. In the south-west, males moult more frequently than females; the opposite is the case for the east and north-east crab stocks. A valid reason for this difference has not yet been established.
Lugworm mortalities and a bloom of Gyrodinium aureolum Hulburt in the eastern Irish Sea, Autumn 1971
Authors: Helm M. M. , Hepper B. T. , Spencer B. E. , Walne P. R.
Published: May 2009

A bloom of the dinoflagellate Gyrodinium aureolum Hulburt in the eastern Irish Sea during September and October 1971 was accompanied by unusual mortalities of Arenicola marina L. and Echinocardium cordatunt Pennant. Observations in the field and laboratory suggest that the mortalities may not have been directly related to the occurrence of Gyrodinium but could have been a consequence of unusual climatic conditions which resulted in oxygen depletion in benthic substrates. The decomposition of the bloom possibly aggravated the situation.
Cephalopods, blue sharks and migration
Authors: Clarke Malcolm R. , Stevens J. D.
Published: May 2009

A small collection of cephalopod remains taken from 26 blue shark stomachs is examined. This includes 92 lower and 97 upper beaks which are identified as far as possible to species. From measurements of the beaks, mean weight and total weight of each cephalopod species is estimated. The presence of oceanic cephalopod remnants in the stomach contents indicates that some sharks caught in the Looe area had recently migrated inshore from deep water.
Cephalopod remains from a sperm whale caught off Vigo, Spain
Authors: Clarke M. R. , MacLeod N.
Published: May 2009

A small collection of cephalopod beaks from the stomach of a sperm whale caught off Vigo is described, identified and the weight of cephalopods represented is estimated. Comparisons are made with a similar collection previously described from a whale caught off Madeira.
Vertical distribution of cephalopods at 30°N 23°W in the North Atlantic
Authors: Clarke M. R. , Lu C. C.
Published: May 2009

A total of 618 cephalopods comprising 29 identified species and 98 young unidentified larvae were collected at 30° N 23° W in opening–closing rectangular midwater trawls (RMT combination net), an Isaacs Kidd midwater trawl equipped with an openingclosing bucket and a British Columbia midwater trawl. Discrete horizons were fished between the surface and 2000 m and day and night vertical distribution for the more common species is described. Material is sufficiently abundant to draw tentative conclusions on the vertical distributions of 16 species. These show a wide variety of migratory and non-migratory behaviour including diel migration, ontogenetic migration and static distribution at various depths and over various depth ranges.
A Complete List of the Opisthobranchiate Mollusca found at Plymouth; with Further Observations on their Morphology, Colours, and Natural History
Authors: Garstang Walter
Published: May 2009

This paper is intended to furnish a complete list of all the species of Opisthobranchiate Mollusca found up to this time by the Marine Biological Association at Plymouth, together with various notes upon their morphology and natural history. The Nudibranchiate section of the group has, however, already formed the subject of a preceding report published in this Journal, so that species which have not since been taken are recorded here by their names only, a fuller account of them being given in the previous report. All the species there recorded are distinguished in this paper by asterisks (*) affixed to their names. I have had the advantage of several works upon the classification of the group which have recently appeared, notably Carus's excellent Prodromus Faunæ Mediterraneæ, vol. ii, part 1, 1889; Bergh's Die cladohepatischen Nudibranchien (Zoolog. Jahrbüch., v, 1890; for a copy of this admirable work I am indebted to the author); and Norman's Revision of British Mollusca (Ann. Mag. Nat. Hist., VI, vol. vi, No. 31, 1890, pp. 60—91). I must also mention Vayssière's Recherches Zoologiques sur les Mollusques Opistobranches du Golfe de Marseille—I. Tectibranches (Ann. Mus. Hist. Nat. Marseille, Zool., II, 1885, Mém. No. 3) as having been of great service; and I regret that up to the time of going to press the second part of M. Vayssière's work has not arrived at the Laboratory, and I have been unable to refer to it.
Gigantism and Variation in Peringia ulvœ Pennant 1777, caused by Infection with Larval Trematodes
Authors: Rothschild Miriam
Published: May 2009

In 1933 an examination of Peringia ulvœ for larval trematodes was under-taken at Plymouth (Rothschild, 1936). No actual measurements were made at the time, but there appeared to be a relation between the species of trematode and the size of the individual infected snails. Thus the commonest species, Cercaria oocysta Lebour, 1907 (14% infection), and C. ubiquita Lebour, 1907 (4% infection), were found in 75% of the largest snails, while the rarer species, such as C. ephemera Lebour, 1907 (non Nitsch) (2% infection), and C. pirum Lebour, 1907 (0–1% infection), occurred most frequently in medium sized individuals.
Notes on the Eggs and Larvæ of Some Plymouth Prosobranchs
Authors: Lebour Marie V.
Published: May 2009

The following short descriptions of several of the eggs and larvæ of Plymouth prosobranchs, hitherto unknown or imperfectly known, are brought together, although many of them are not fully worked out. It is hoped in the near future to publish a general account of the British species with reference to all known forms, including those which have been specially described from Plymouth.

Some of those described below have not yet been identified, but it is thought that it is worth while noting them for the benefit of future workers, especially some striking forms, important in the plankton on account of their size. This is notably the case with the three larvæ probably belonging to the Turridæ.
The Development of Audouinia tentaculata (Montagu)
Authors: Wilson Douglas P.
Published: May 2009

(1) Adults of Audouinia tentaculata Montagu were induced to spawn in the laboratory; the eggs were fertilized and the larvæ reared to metamorphosis and early bottom stages for the first time.

(2) The larvæ are yolky and do not feed. They have a broad prototroch and telotroch and a broad neurotroch. The ciliation of the head is rather complex. There are no bristles. When about ten days old they metamorphose.

(3) During metamorphosis most of the cilia, except those of the neurotroch, disappear and their cells are absorbed internally.

(4) Bristles appear for the first time a few days after metamorphosis. After a while branchiæ appear, followed by what are apparently tentacular filaments situated on segments anterior to those on which they occur in the adult.

(5) Discussion centres on the position of the tentacular filaments and the first pair of branchial filaments in the young worm as compared with the adult. The segmentation of the anterior achaetigerous region also receives attention.
Rays and Skates. No. 2.—Description of Embryos
Authors: Clark Robert S.
Published: May 2009

In the years 1921 and 1922 a series of experiments on the rearing and hatching of the species of Rays and Skates occurring on the English side of the western end of the English Channel was carried out at the Laboratory of the Marine Biological Association, Plymouth. The egg-capsules were collected from fish landed at the Barbican at Plymouth and from fish captured by the Research steamers, Oithona and Salpa. The egg-capsules were kept in the circulation of sea-water in the tanks at the Laboratory, and for six species the period of incubation under these artificial conditions was determined.
Investigations Upon the Water Movements in the English Channel. Summer, 1924
Authors: Carruthers J. N.
Published: May 2009

In July, 1924, 250 floating, and an equal number of bottom-trailing, bottles were put out at selected places in the western English Channel. Fifty of each type were put out at each of the two routine Stations E2 and E3, and the same number was “liberated” at each of three selected stretches along the steamship route from Southampton to St. Malo. Those surface bottles, which did not strand locally, travelled rapidly up Channel towards the North Sea and across it. Many bottles arrived in the Skager-Rack after performing their journey of some 700 miles at the rate of 6 miles a day and more. An adequate study of wind conditions, as recorded at several stations along the length of the Channel and at one station in the southern North Sea, revealed the fact that there was, for some 5½ months (counting from the time of liberation of the bottles), an almost uninterrupted predominance of south-westerly winds—as recorded at all stations considered. The whole area of the Channel was swept by south-westerly winds of average speed of some 9 miles a day for at least 5½ months subsequent to the time of putting out of the bottles. July, 1924, had (according to the Falmouth Observatory records) the largest proportion of westerly winds experienced for 54 years; 20 days of this month had winds with westerly components. The association of the unusually persistent westerly winds with the rapid travel of surface bottles towards and across the North Sea is interesting.
Temperature and Enzyme Activity
Authors: Baker John R.
Published: May 2009

The enzyme contained in the crystalline style of Pecten is destroyed more and more rapidly as temperature increases. On the other hand, it becomes more and more active if incubated at fairly low temperatures, possibly as a result of the progressive dispersion of the protein base on which it is absorbed. A graph has been calculated showing the effect of temperature on enzyme activity when both destruction and (?) dispersion are discounted.
The Ability of Fishes to Extract Oxygen at Different Hydrogen Ion Concentrations of the Medium
Authors: Pruthi Hem Singh
Published: May 2009

Powers, working on some marine fishes, arrived at the important conclusion that the ability of fishes to absorb oxygen at low pressures is more or less dependent upon the hydrogen ion concentration of the water. His method of research was briefly as follows: a fish was placed in a two-quart jar filled with water, which was closed airtight with a rubber stopper. The pH and the oxygen determinations were made immediately after all the movements of the fish had ceased. The amount of oxygen left at death represented, according to Powers, the pressure below which the fish at the particular pH could not extract any more oxygen from water. Powers did not control the amount of oxygen at the beginning of an experiment; he says, “it was always sufficiently high so that the fish did not at first suffer from oxygen want.”
Irregular Development in the Larval History of Meganyctiphanes norvegica
Authors: Macdonald Roderick
Published: May 2009

A new type of Nauplius belonging to Meganyctiphanes norvegica is described.

Attention is drawn to irregularities in the development of the furcilia forms in which particular stages are sometimes omitted.

It is suggested that in the larval history of M. norvegica in common with other Euphausids there is an indication of evolutionary progress in the group Euphausiaceæ.
Preliminary Observations on the Chemistry and Biology of the Lorica in a Collared Flagellate (Stephanoeca Diplocostata Ellis)
Authors: Leadbeater B. S. C. , Manton I.
Published: May 2009

Evidence for the presence of silica in the costae of Stephanoeca diplocostata Ellis has been provided by a combination of light and electron microscopy. The solubility of costae in hydrofluoric acid has been demonstrated. The presence of silicon in the costae has been strongly confirmed by means of the X-ray analytical electron microscope (EMMA) but tests for a crystalline substructure by means of electron diffraction were negative; it is concluded that silicon is present in a crystallographically amorphous form. Preliminary observations on other biological aspects of the organism include the presence of a sac-like membrane between the lorica and protoplast, the presence of immature costal strips within the cytoplasm and the nature of ingested food. The phyletic position of the group is briefly discussed with special reference to mitochondrial substructure.
Observations on the Occurrence of an Epizooic, Blue-Green Alga on the Chemoreceptor Setae of the Brown Shrimp, Crangon Crangon (L.)
Authors: Shelton R. G. J.
Published: May 2009

The thin-walled setae on the outer rami of the antennules of decapod Crustacea are considered to be chemoreceptors. It is not known whether stimulatory molecules enter each seta through the cuticular wall or via an apical pore. In this paper evidence is presented that the antennular chemoreceptors of the brown shrimp, Crangon crangon (L.), bear apical pores. In some field and laboratory populations, however, the pores are blocked by an epizooic, blue-green alga and this provides a direct means of testing the hypothesis that the apical pore is important in the sensory process.
Growth and Moulting in the Common Lobster(Homarus VulgarisMilne-Edwards)
Authors: Hewett C. J.
Published: May 2009

Data collected over a period of 15 years for lobsters maintained at 10 °C and weighingfrom < 1·0 to 1200 g have been analysed. Equations have been produced defining the relationships of the cast shell weight, the growth increment at the moult, the inter-moult period and the food intake per moult with the weight of the lobster, and of the growth increment with the food intake. In particular, a growth curve has been derived showing the weight of lobsters, kept at 10 °C, with age. It is suggested that when there is an adequate food supply, the growth increment is a constant proportion of the lobster weight, and that variations in growth rate are achieved by changes in the length of the inter-moult period which, in turn, is mainly dependent upon the temperature of the environment.