bluuebunny/crossref_metadata_2025_split huggingface dataset:
Note on a Marine Labyrinthula
Authors: Jepps Margaret W. 
Published: May 2009

Plasmodia of Labyrinthula almost invariably appear in the diatom cultures and other small marine aquaria which I have kept during the last several years for a variety of purposes in Glasgow. These aquaria are stocked with material from Millport, I. of Cumbrae, and I think it quite certain that the Labyrinthula is imported thence.This amazing creature has attracted interest ever since it was first described by Cienkowski in 1867, and good figures of it have been published by Cienkowski (1867), Duboscq (1921), and Valkanov (1929). The following note is to be regarded as a commentary on previous work and a record of my own observations rather than as an exhaustive account of the organism.
Changes in Length during the Larval Life and Metamorphosis of the Freshwater Eel (Anguilla uulgaris Turt.)
Authors: Ford E. 
Published: May 2009

In other papers (Ford, 2 and 3) attention was directed to a study of the changes in length which occur during the transformation of the transparent eel-shaped larval clupeoid into the silvery and scaled adolescent fish. The change in position of the anus and fins relative to the vertebræ was considered in connection with the altering proportions of the different body intervals as development proceeds, and simple models were used to illustrate important features.Now the freshwater eel has its transparent larval stage and metamorphosis. As in the clupeoid, length-proportions change during development, while anus and fins undergo marked migrations with respect to the myomeres. It was therefore thought to be of no little interest to analyse the length-changes during development in a manner similar to that adopted for the herring, sprat and pilchard. Professor Johannes Schmidt most kindly supplied me with material upon which to work, and I have made much use of data already published by him in reports on his great pioneer investigations. I have also drawn extensively from the data given by Dr. Leon Bertin in his paper on the migrations of the anus in the eels during ontogeny. I may be permitted to add that much which follows is suggestive in nature, rather than proven fact. Nevertheless, it should prove of interest in its direct bearing upon questions of fundamental biological importance.
Relative Growth of the abdomen and the carapace of the Shore-CrabCarcinus maenas
Authors: Huxley J. S. , Richards O. W. 
Published: May 2009

1. In regard to relative abdomen-breadth and relative carapace-breadth, the common shore-crabCarcinus maenasin both sexes exhibits a continuous change of proportions throughout life, from small animals of 2 mm. carapace-length to the largest obtainable (over 50 mm. carapace-length).2. The parts measured exhibit constant differential growth-ratios (growth-coefficients) relative to carapace-length taken as standard, over long periods of the life-history.3. The approximate growth-coefficients are as follows, relative to carapace-length:Carapace-breadth, 1·06. This appears to be constant throughout the range of size measured, with a possible decline to nearly unity at large sizes.Abdomen-breadth.Crabs unsexable externally (2–6 mm. carapace-length), 1·26.Females: early phase, 1·26; late phase, 1·42.Males: early phase, 1·07; late phase, 0·94.The early phase begins as soon as the sexes can be distinguished. The onset of the late phase may be presumed to be correlated with sexual maturity. In females it occurs certainly between 17 and 20 mm. carapace-length, in males between 14 and 29 mm.4. There are indications of seasonal and local differences in relative abdomen size.5. Feeding crabs of 9 to 22 mm. carapace-length solely on fresh ox-thyroid or fresh ox-pituitary for periods up to a year produces no change in growth-rate or in secondary sexual characters as against controls fed on fresh fish.
A photographic survey of certain areas of sea floor near Plymouth
Authors: Vevers H. G. 
Published: May 2009

An improved underwater photographic apparatus has been used to take further series of photographs of the sea bottom near Plymouth. The photographs in the present series are each ¼ m.2 in area instead of 1 m.2, and at this scale definition is much better.Photographs of the bottom in the Rame Mud area showed ripple marks but no living epifaunal animals. In an area south of the Rame Mud, on a muddy sand and gravel bottom and in a similar area 6 miles south of Looe, dense populations of the brittle-star, Ophiothrix fragilis were photographed. In the area south of Looe this type of population (density more than 100 individuals per m.2) ha s been photographed on three different occasions in 1950–1. In a similar but still denser Ophiothrix population found ¾ mile north-west of Eddystone, there were about 340 individuals per m.2, and this aggregation was apparently of long standing, since exceptionally large dredge hauls of Ophiothrix were taken there in the last decade of the nineteenth century. It is suggested that the food supply for these populations, in the form of suspended material, is brought to them largely by the tidal streams and that the crowded beds are in localities where this is likely to happen.
Ecological and non-environmental constitutional resistance of the protoplasm of marine algae
Authors: Biebl Richard 
Published: May 2009

Marine algae supply good examples of the difference between ‘ecological’ and ‘non-environmental constitutional’ resistance of the protoplasm of their cells to variations in the environment. The resistance to ecological factors such as diluted or concentrated sea water, to desiccation, or to light exposure is very similar among algae occupying the same habitat. On the basis of the degree of resistance shown, three ecological groups can be distinguished: (1) algae from the intertidal zone; (2) algae from the low-water level and tide-pools; and (3) sublittoral algae.On the other hand, there is no similarity in the resistance to chemical substances (H3BO3, ZnSO4, MnSO4, VOSO4) of algae within a given ecological group. It is characteristic for a given species.
Studies on the parasites of Cardium edule L.: Cercaria fulbrighti n.sp., a Gymnophallus larva with a forked tail
Authors: Hutton Robert F. 
Published: May 2009

A summary of the trematode parasites which have been recorded from the cockle is given.A furcocercous, Gymnophallus larva, Cercaria fulbrighti n.sp., from the marine bivalve Cardium edule L., is described from Plymouth, England. The tail of this larva may degenerate completely while the cercaria is still within the sporocyst.Simultaneous development of more than one species of cercaria has been recorded in four out of 420 specimens of C. edule L. Two double and two triple infections were found.Available evidence suggests a phylogenetic relationship between the Gymnophallus group and certain of the Furcocercous cercariae.
Further experiments on biological differences between natural sea waters
Authors: Wilson Douglas P. , Armstrong F. A. J. 
Published: May 2009

In one experiment sea water from the Firth of Clyde yielded better cultures of Echinus esculentus larvae than did sea waters from two positions in the English Channel.From the Clyde water materials of unknown composition were extracted, using active carbon and acetone. The addition of these materials to both Clyde and Channel waters resulted in the death of the Echinus eggs during early cleavage. A similar extraction from Channel water had the same effect. The Clyde and Channel waters from which these materials had been extracted gave poor abnormal cultures, especially the Channel water in which most larvae died early. A few, however, survived, and later on some of these grew into almost normal plutei.
Effects on Dietary Lipids of the Marine Bivalve Scrobicularia Plana Feeding in Different Modes
Authors: Bradshaw Stuart A. , O'Hara Sean C.M. , Corner Eric D. S. , Eglinton Geoffrey 
Published: May 2009

Changes in dietary lipids were investigated in laboratory feeding experiments simulating herbivorous and coprophagous modes of feeding in the bivalve mollusc Scrobicularia plana (da Costa). The dinoflagellate Scrippsiella trochoidea (Stein) was used as the food in herbivory experiments while faeces from the crustaceanNeomysis integer (Leach) feeding on Scrippsiella were used as the food in coprophagy experiments. Changes in dietary total fatty acids, sterols and fatty alcohols were characterised by analyses of the food, faeces andanimal tissues using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).There is a net decrease in the total lipid of the digested material during both herbivory and coprophagy. However, while fatty acids are assimilated, sterols are contributed to the faeces, leading to a decrease in the fatty acid:sterol (FAST) ratio of the digested material. Coprophagy decreases the ratio still further, such that faeces have a FAST ratio of <1Scrobicularia preferentially assimilates dietary polyunsaturated fatty acids (PUFAs). Reworking of sedimentary material (as in coprophagy) will lead to PUFA-deficient sedimentary fatty acid distributions. Both herbivory and coprophagy lead to relative increases in 'bacterial' odd carbon-number normal and branched fatty acids in the digested material, though not the 'bacterial' marker 18:1 Benthic molluscan feeding, particularly coprophagy, contributes partly to the 'bacterial' fatty acid content of the sediments.Scrobicularia contributes its own sterols to the faeces, especially cholesterol. Such contributions aredependent on the dietary sterols present. With a cholesterol-poor diet (herbivory), A5 4–desmethyl sterols are contributed to the faeces and dietary A8(14) sterols decrease, suggesting a A8(14) U021e2; A5 conversion may occur. With a cholesterol-rich diet (coprophagy), the A5 sterol is taken up from the diet.
The Age Structure and Growth Dynamics of Young-Of-The-Year Bass, Dicentrarchus Labrax, Populations
Authors: Jennings S. , Lancaster J. E. , Ryland J. S. , Shackley S. E. 
Published: May 2009

Back-calculated egg fertilization (spawned) dates and growth rates for young-of-the-year bass, Dicentrarchus labrax (L), captured from Loughor Estuary, Oxwich Bay and Ogmore Estuary, south Wales, UK, during 1988 and 1989 were compared. Spawned date frequency distributions indicated that the bass spawning season began in late February and continued until early June in 1988 and early July in 1989.There were no significant differences in the frequency distributions of back-calculated spawned dates for the bass populations, between either sites or years, which suggested that any variations in growth rates were attributable to characteristics of their respective environments. Growth rates were determined for bass cohorts resulting from early, midor late-season spawnings at Oxwich and Loughor in 1988 and Oxwich, Loughor and Ogmore in 1989. There were only slight intra-annual differences between the mean growth rates of bass cohorts at the same site, suggesting that bass from early cohorts would be larger at any given time of year. In 1989, growth was considerably faster at Oxwich and Loughor than at Ogmore, where food supply was considered limiting. However, between-site variations in growth rate were small in comparison with inter-annual differences. The faster growth rates observed at Loughor and Oxwich in 1989 were attributed to higher water temperatures.Relationships between growth rate and subsequent survival of young-of-the-year bass, and the relative importance of estuaries as nursery habitats for juvenile bass, are discussed.
Seasonal Variation in Pilayella Littoralis (Phaeophyceae) and its Consequences as a Food Source for the Amphipod, Gammarus Lawrencianus, in the Intertidal of Newfoundland
Authors: Steele D. H. , Whittick A. 
Published: May 2009

The brown alga Pilayella littoralis is common and widely distributed in the North Atlantic. In insular Newfoundland it is found year-round in the subtidal, but shows a distinct periodicity in the intertidal where it is a summer annual. Rapid growth begins in May and a maximum biomass is achieved in the summer with plants disappearing by October. Besides seasonal changes in abundance, seasonal changes in reproductive behaviour and calorific values of this alga also occur.Pilayella littoralis is the most abundant consumable alga available to intertidal amphipods in Newfoundland. Newly hatched Gammarus lawrencianus grew faster and matured at a younger age on a diet of summer P. littoralis than on plants collected in the spring. Size at maturity and reproductive output (size of eggs, number of eggs) of maturing females did not vary with the time of collection of Pilayella.
The Habits of the Angler-fish, Lophius piscatorius L., in the Plymouth Aquarium
Authors: Wilson Douglas P. 
Published: May 2009

1. Young angler-fishes have been kept alive and in health for periods varying from a few weeks to eleven months. They were sometimes hand-fed on dead fishes and sometimes allowed to catch living prey. They grew at an average rate of about eight and a half inches per annum. All had strongly marked individual characters.2. With pelvic and pectoral fins a slight hollow is made in the sand into which the angler settles itself. Its upper surface is now flush with the ground, and the colour and colour mottlings are closely matched to the surroundings. The bordering tags of skin break up the outline.3. Breathing movements occur at relatively long intervals. The expiratory currents are discharged in the axils between the pectoral fins and the trunk, and are deflected vertically upwards.
The Air Turbine Ultracentrifuge, together with some Results upon Ultracentrifuging the Eggs of Fucus serratus
Authors: Beams H. W. 
Published: May 2009

1. An air turbine ultracentrifuge suitable for biological work and capable of developing a centrifugal force from 10,000 to 500,000 times gravity has been described. Advantages of the ultracentrifuge are: (1) The temperature does not vary in the centrifuge chamber over 2 or 3 degrees from that of the atmosphere; this is not sufficient to be an important factor in general biological work. (2) The cost of constructing the apparatus is very low in comparison with that of other high speed centrifuges.2. A modification of the air turbine ultracentrifuge in which the turbine rotor drives a second rotor, in this case the centrifuge rotor which spins in a vacuum, has been described. Here the centrifuge chamber is thermally insulated which is an important item in preventing troublesome convection currents from arising in the centrifuged material where such special problems as the rate of molecular sedimentation are being observed. Forces in excess of one million times gravity can easily be obtained by such an apparatus.
The Fauna of Certain Estuaries in West England and South Wales, with Special Reference to theTanaidacea, IsopodaandAmphipoda
Authors: Crawford G. I. 
Published: May 2009

Duringthe summer of 1935 Captain Nicholson of Saltash kindly put his motor-boat at my disposal and took me for seven full-day collecting trips on the estuaries of the Tamar and its confluents, the Tavy and Lynher. I also made some collections from land in the estuaries of the Plym and Exe (S. Devon), Taw (N. Devon), Camel (N. Cornwall), and Towy (S. Wales).All collecting was done intertidally or in shallow water and was practically confined to the brackish-water reaches. No gear was used except a hand-net of stramin, and a zinc sieve of 1-mm. mesh. More attention was paid to the Crustacean orders Tanaidacea, Isopoda, and Amphipoda than to the rest of the fauna, observations on which were only occasionally made.
The ecology, distribution and taxonomy of the centipedes found on the shore in the Plymouth area
Authors: Lewis J. G. E. 
Published: May 2009

Six species of geophilomorph centipede are reported from the littoral zone in the Plymouth area, and in two cases, where they differ from previous descriptions, the significance of these differences is discussed. It is suggested that the various British and French populations of Geophilus algarum and Geophilus fucorum may be subspecies of one polytypic species.It is shown that Strigamia maritima and Hydroschendyla submarina differ in the way in which they have adapted to life on the shore. The former lays permeable eggs and migrates out of the littoral zone to lay them and to moult, the latter lays impermeable eggs and moults in the intertidal zone. Information on the prey of S. maritima at Plymouth is given.The variations between some populations of littoral centipedes is discussed and possible reasons for the high density of populations of S. maritima and H. submarina are given.
A cubical photometer for studying the angular distribution of submarine daylight
Authors: Atkins W. R. G. , Poole H.H. 
Published: May 2009

Preliminary observations have been made in the English Channel off Plymouth on the average obliquity of illumination under water, and on the relative intensity of light reflected upwards at various depths, the readings being made with a cubical photometer containing six “Electrocell” selenium rectifier cells mounted behind opal glasses and Jena VG 9 (green) filters. The cells measured the light of wave-lengths about 480–580 mμ falling on upward-and on downward-turned horizontal surfaces, and on four vertical surfaces i n rectangular azimuths.The average angle with the vertical or of obliquity was from 36 to 40°, and no significant difference could be detected between that for smooth sea and overcast sky, and that for rough sea and either high or low sun. Figures for smooth sea and sunlight are more difficult to obtain, as in the absence of drift due to wind the photometer may rotate.No decrease in average obliquity with depth was found, in some cases there was evidence of a slight increase. This is in accordance with our previous results, and accords well with the constancy of extinction coefficient so often found throughout a series. It is not, however, in agreement with the careful work of Johnson & Liljequist, so further determinations would seem to be desirable.The percentage of the light which was scattered back so as to fall on a downward-turned surface varied from 5.5 for comparatively opaque water (extinction coefficient 0.20) inside Plymouth breakwater, to 2.1 for very clear water (extinction coefficient 0.076) some miles off at sea. The presence or absence of sunlight had little effect, values close to 3.0 being obtained with and without sun for water having a coefficient close to 0.110.
Fluctuations in oyster production in the Fal Estuary
Authors: Orton J. H. 
Published: May 2009

A survey of the Fal Estuary Beds in February 1939 gave evidence that the stocks of oysters were only slightly better than in the slump period of 1926.The failure of the beds to show the recovery expected in recent years is attributed largely to the absence of sufficient clean culch on the banks.It is suggested that means be taken to scatter clean culch over the banks in June yearly to prevent further decline of the beds and assist in their more rapid recovery to a flourishing condition.The American slipper limpet, Crepidula fornicate, was not found and appears to be unknown on the beds.
The rearing of oyster larvae on an algal diet
Authors: Bruce J. R. , Knight Margery , Parke Mary W. 
Published: May 2009

The work described in this paper is a contribution to the general problems of rearing the larvae, and growing the spat of the European flat oyster, Ostrea edulis L.The specific aspect of the problem dealt with in detail is the place taken by minute motile organisms (naked dinoflagellates and other unicellular algae) in the food requirements of the developing veliger larvae.Six such flagellate organisms, ranging in size from 1·5 to 7 μ in diameter, have been isolated from sea water, and are maintained in pure culture, under conditions described. Pending specific identification, these are denoted by letter-labels only. These organisms have been used, over a period of years, in feeding experiments with oyster larvae.
The fecundity of Ostrea edulis
Authors: Cole H. A. 
Published: May 2009

It is shown that the average number of embryos produced by a gravid oyster is approximately doubled each year until the oyster is 4 years old, when it may be regarded as adult. Estimates have been made of the quantities of embryos produced by one 1-year-old, eleven 2-year-old, fourteen 3-year-old and twenty-two adult oysters; the mean values for these year-classes are 91,600, 218,100, 462,600 and 902,900 respectively.Since it is probable that the proportion of a population of oysters which matures in the female phase increases progressively up to the age of 4 years, it follows that adult oysters are for this reason superior to 2- or 3-year-old oysters as breeding stock, quite apart from the increased number of embryos produced by each oyster.
Metric variations in populations ofCarcinus moenas
Authors: Williams G. , Needham A. E. 
Published: May 2009

1. Measurements ofCarcinus, comparable to those taken by Weldon at Plymouth 40 years ago, have been made on material from three Irish localities, the observations in each area extending over three years. The three localities afford different environments, one having no silt, one a moderate amount and the other much silt.2. The results support the view that the change in the ratio frontal width/ carapace length with increase in body size is due to differential growth in the individual and is not caused, as Weldon supposed, by the continuous removal through natural selection of those crabs with a relatively wide frontal aperture. Measurement on the growth of individuals confirms this view.3. A striking fact which emerged from Weldon's work was that the ratio mentioned above showed a successive diminution in each of the three years covered by the observations. A precisely similar diminution has been found at each of the Irish localities, and it is shown that the annual differences are mathematically significant.4. The results disprove Weldon's hypothesis that the change in the ratio is correlated with the slow accumulation of silt in Plymouth Sound. The Irish locality with most silt has the widest frontal aperture and the intermediate locality the narrowest. It is also shown that the yearly trend towards a lower value for the ratio cannot be continuous, for the rate of change is too rapid to be maintained indefinitely, and the values obtained in the Irish localities overlap those at Plymouth 40 years earlier. Possible explanations of the changes are discussed.5. The differences between populations from the three localities in any year are much less marked than the annual differences at one locality, and are not generally significant. Though small, however, they do show a consistent sequence among the three localities (but not corresponding to the order for siltiness).