bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benthic Egg Masses and Larval Development of Amblyosyllis Speciosa (Polychaeta: Syllidae)
Authors: Pernet Bruno 
Published: May 2009

Eggs of the syllid polychaete Atnblyosyllis speciosa are deposited in benthic gelatinous masses. Embryos and larvae develop within these masses until about three weeks after fertilization, after which they crawl or swim away and metamorphose. Only one other syllid, the Mediterranean Syllides edentula, has been reported to form benthic egg masses.While some syllid polychaetes spawn gametes freely into the water column where they are fertilized and develop without additional parental care, most species protect developing embryos in some fashion. Four modes of brood protection have been reported in the syllids. Protection of embryos within the ventral brood chamber of a planktonic adult is characteristic of members of the subfamily Autolytinae, and of some members of the Eusyllinae (Garwood, 1991). Physical attachment of embryos to the body of the maternal parent (external gestation) occurs in all members of the Exogoninae and in a few eusyllines (Heacox & Schroeder, 1978; Garwood, 1991). Viviparity is less common, having been reported in a few species in the subfamily Syllinae (Schroeder & Hermans, 1975; Ben-Eliahu, 1975) and in one exogonine (Pocklington & Hutcheson, 1983). Finally, the formation of benthic egg masses has been described in only one species, the eusylline Syllides edentula Claparède (Cognetti-Varriale, 1971).In this study the benthic egg masses and development of another eusylline, Amblyosyllis speciosa Izuka, 1912, are described. In December 1995, at the Friday Harbor Laboratories (FHL), Washington, USA, five adult worms were found on a bivalve shell heavily infested with the boring sponge Cliona sp. Additional specimens and egg masses were collected in June 1996 and April-June 1997 from encrusting sponges on the FHL breakwater.
The Rate of Liberation of Phosphate in Sea Water by the Breakdown of Plankton Organisms
Authors: Cooper L. H. N. 
Published: May 2009

Samples of animal and plant plankton were added to sea water in glass vessels and the subsequent changes in the phosphate content of the water were followed.The breakdown of the zooplankton was very rapid and more phosphate was set free than had originally been added as plankton. The balance was produced from dissolved organic phosphorus compounds in the water. The breakdown of phytoplankton showed a short time lag and only a part of the phosphorus added was set free as phosphate.
The Ecology of a Salt–Marsh
Authors: Nicol A. T. 
Published: May 2009

The salt-marsh under investigation is situated at Aberlady Bay on the south shore of the Firth of Forth, fifteen miles east of Edinburgh.The marsh is small and occurs at the mouth of a stream. The character of the soil on the two banks differs, being on the one side muddy with permanent pools, and on the other sandy, so that the pools tend to drain dry. The vegetation of the pools is variable, some containing species of Zostera, Ulva, Enteromorpha and Vaucheria, others having only diatoms.
Tunny Investigations made in the North Sea on Col. E. T. Peel's Yacht, “St. George,” Summer, 1933. Part I. Biometric Data
Authors: Russell F. S. 
Published: May 2009

1. Details are given of the types of hooks lost in tunny in the North Sea in the summer of 1933.2. Data are given on the measurements made on thirty-two large migrating fish caught in the North Sea in August and September, 1933.3. In certain body proportions the tunny measured differ from those in the G4 Group (200 to 260 cm. in length) given by Heldt for fish from Tunis and by Frade for fish from Algarve on the south coast of Portugal, while in some characters they resemble the Tunis fish and in others the Algarve fish, but all the North Sea fish were between 232 and 271 cm. in length.4. It was found that there was a tendency for fish with short second dorsal fins to have short first dorsal, anal, and caudal fins, and for those with long second dorsals to have these other three fins long.5. Measurements were made to supply data on the condition of the fish.
Variations in the Amount of Macroplankton by Day and Night
Authors: Gardiner A. C. 
Published: May 2009

1. Twenty oblique hauls of a stramin ring-trawl, diameter of mouth 5 feet, were made during a period of 48 hours off Liverpool, Nova Scotia, i n May, 1932.2. The common species were Thysanoëssa mschii, Th. inermis, Sagilta elegans, Calanus finmarchicus and C. hyperboreus.3. All of the above occurred in the collections made during the night n i larger numbers than in those in the daytime. No such discrepancy appeared in the case of the Fish Ova.4. The discrepancy is held to be due in each case to a proportion of the population sinking to depths greater than could be sampled by the net.
The Use of a Selenium Rectifier Photo-electric Cell for Submarine Photometry
Authors: Poole H. H. , Atkins W. K. G. 
Published: May 2009

1. Measurements of the penetration of light of various colours into the sea were carried out by means of a selenium rectifier cell. The mean vertical absorption coefficients were: for blue, 0·177; green, 0·153; “white,” viz. no filter, 0·216; yellow, 0·243; red, 0·345. The results accord well with those obtained under similar conditions with emission cells and show that, for water a couple of miles offshore, green light penetrates best.2. The current was measured using the potentiometer-telephone method as for emission cells, but determining the drop in potential across a low resistance, 10,100, or 1000 ohms. The motion of the ship was too violent to permit of the use of any available galvanometer of adequate sensitivity.3. Rectifier cells are more convenient to use than emission cells, as the currents to be measured are much larger and the absence, of high potentials greatly simplifies all insulation problems. On the other hand the curvature of the illumination–current relation involves additional labour in standardizing and in calculating results.
The Population cycle of the bivalve Abra tenuis and its mode of reproduction
Authors: Gibbs P. E. 
Published: May 2009

The annual cycles of the Abra tennis populations in the Plym Estuary and the Fleet (Dorset) were studied from March 1980 to June 1982. In the Plym Estuary the highest numbers occurred in autumn following juvenile recruitment and the lowest numbers were recorded in mid-summer. In the Fleet such an annual cycle in numbers was not apparent since juvenile recruitment in 1980 was very high but in 1981 it was very low. The recruitment failure in 1981 may have resulted, at least in part, from the heavy summer infection of A. tenuis by digenean parasites that destroy the gonads of the host, thereby reducing the population fecundity.A. tenuis spawns in July and August: the mature egg has a diameter of 140 μm and is enclosed in a sticky gelatinous envelope. Females produce 450–1800 eggs which, when fertilized, are laid in a mass within the sediment and, following a direct development, the juveniles hatch as miniature adults after 2–3 weeks. This non-pelagic, lecithotrophic development is interpreted as being a means of ensuring the maintenance of populations within restricted estuarine habitats. Data suggest A. tenuis lives for 1 or 2 years and that the species is monotelic.
Nutrient stimulation of carbon fixation in summertime English Channel phytoplankton assemblages
Authors: Davies Anthony G. , Sleep Jillian A. 
Published: May 2009

The effects of nutrient additions and zooplankton excretion products upon carbon fixation rates in the phytoplankton present at Station L 4 in the English Channel during the summer and autumn of 1979 have been studied. Nitrate, ammonium, urea, phosphate, glucose-6-phosphate and the excretion products when added individually all caused photosynthesis to be stimulated, and the result of the simultaneous addition of nitrate and phosphate indicated that their effects were additive. Germanic acid, which inhibits photosynthesis mainly in diatoms, removed the stimulatory effect of the nitrogen supplements, indicating that they were utilized mostly by the diatoms; the higher fixation rates caused by the phosphate enrichments were, however, decreased by the same proportion as the unenriched controls when germanic acid was present, suggesting that the whole of the phytoplankton population was phosphorus-limited. This was supported by the finding that glucose-6-phosphate stimulated carbon fixation in all of the phytoplankton.The excretion products, even at concentrations likely to be produced in the sea, stimulated carbon fixation, and it has been calculated that zooplankton-regenerated nitrogen and phosphorus compounds could supply the amounts needed to maintain primary production during the summer period.Nutrient additions and zooplankton excretion products had little effect upon carbon fixation in the autumn samples, presumably because the higher nutrient levels then present in the water exceeded the requirements of the phytoplankton.It has been concluded that the predominance of the sub-10μmicroflagellates in the summertime is probably due to their ability to utilize more efficiently than the other types of phytoplankton the low levels of nutrients which become available due to regeneration.
The Loss of the Eye-pigment in Gammarus chevreuxi. A Mendelian Study
Authors: Allen E. J. , Sexton E. W. 
Published: May 2009

Sections I and II. Amongst the stock of Gammarus chevreuxi which had been kept under Laboratory conditions for at least two years a small number of animals appeared in which the coloured retinal pigment was absent, whilst the white extra-retinal pigment remained. The experiments described in the present paper have shown that these eyes were of two different kinds.Eyes of the first kind were derived from a stock which originated in a cross between Black-eyed and Red-eyed animals, and were degenerate and irregular in shape. Four animals of this kind appeared in one brood, and such eyes have since been seen only in direct descendants from these. Eyes of this kind were found to behave as simple Mendelian recessives to eyes showing coloured retinal pigment, whether that pigment was red or black, and they are referred to in this paper as “albino” eyes.
Short-wave absorbing pigments in the ocular lenses of deep-sea teleosts
Authors: Douglas R. H. , Thorpe A. 
Published: May 2009

This study describes the spectral characteristics between 250 and 700 nm of lenses from 71 species of deep-sea teleost. The majority of these did not contain detectable amounts of short-wave absorbing pigment and transmitted all longer wavelengths to the same extent before cutting off smoothly and rapidly in the near-UV (50% transmission 310–348 nm). The lenses of 15 species, however, contained significant amounts of short-wave absorbing pigment. The majority of these lenticular pigments had smooth ‘bell-shaped’ absorbance spectra with a single peak in the near-UV. Such ‘simple’ pigments were extracted from four species (λmax: 360·8 nm, 36·50 nm, 395·7 nm, 324·8 nm) and detected in a further eight species, although insufficient material was available to allow their extraction from the latter group.The absorbance profiles of lenses from another three species were more complex, suggesting the presence of one and two carotenoid-like pigments respectively in the lenses ofArgyropelecus sladeniandA. affinis,and two as yet unidentified pigments in the lenses ofMalacosteus niger.This brings the total of short-wave absorbing pigments so far described in the lenses of deep-sea fish to at least eleven. InArgyropelecusspp. the pigmentation was most pronounced in the lens cortex, while inMalacosteus nigerit was restricted to the lens core. In all other species the pigment appeared freely diffusible throughout the lens. Several species showed an increase in the degree of lenticular pigmentation in older animals and two(Argyropelecus affinisandMalacosteus niger)demonstrated age-related changes in the relative concentrations of two different pigments within the lens.
The Plymouth Mackerel Fishery of 1889—90. From Data collected by Mr. Wm. Roach, Associate Member M. B. A.
Authors: Calderwood W. L. 
Published: May 2009

The returns kindly sent in by Mr. Roach have been tabulated in the following pages.The period during which Mr. Roach made his observations extends from October 23rd, 1889, to September 29th, 1890.Concerning the particular localities in which the fish have been caught, it may be useful, for those who are not familiar with the coast, to explain that the fish make their appearance on the coast at a considerable distance to the east of Plymouth (18—20 miles). The shoals then appear to travel in a westerly direction, some going off into deeper water, all moving about in a more or less uncertain manner. The head-quarters of the fishery eventually become fixed south of Plymouth and Eddystone Light. Gradually the fish seem t o approach the shore, swimming now in large shoals. Many enter Plymouth Sound and are taken in comparatively shallow water, while others travel west, also in shallow water. The “remarks” for August are instructive. We find that, besides the ordinary and large fish, there are also “small fish about the size of pilchards” in the Sound, that “numerous large shoals” are noticed, and that at a later date the fish “seem to be leaving Plymouth Sound.” On September 1st we find the note that “the mackerel are going off into open water and the shoals breaking up.” On the breaking up of the shoals the mackerel fishing is considered to be at an end.
Squalotrema llewellyni gen.nov., sp.nov., a monocotylid monogenean from the nasal fossae of the spur-dog, Squalus acanthias, at Plymouth
Authors: Kearn G. C. , Green J. E. 
Published: May 2009

A description is given of Squalotrema llewellyni gen.nov., sp.nov., a monocotylid monogenean from the nasal fossae of the spur-dog Squalus acanthias. The parasite differs from representatives of other monocotylid genera in the number and arrangement of loculi on the haptor. In order to accommodate the genus Squalotrema, the diagnosis of the subfamily Merizocotylinae (Yamaguti, 1963) has been amended.The eggs differ in shape from those of other monogeneans. Each egg appears to be derived from a tetrahedron by flattening of one of the four apices. A long, coiled appendage projects from the flattened apex and the face of the egg from which the appendage projects also bears two spurs. The curved body of the fully developed, ciliated oncomiracidium occupies only two of the three rounded corners of the egg.
The Biology of Fish of the Family Moridae in the Deep-Water of the Rockall Trough
Authors: Gordon J. D. M. , Duncan J. A. R. 
Published: May 2009

The morid fishes are important members of the deep-water associations of fish on the continental slope of the Rockall Trough. Three species, Lepidion eques, Halargyreus johnsonii and Mora moro, are distributed between about 500 and 1250 m while Antimora rostrata has its centre of abundance between about 1750 and 2200 m. Aspects of their biology including changes in abundance and length composition with depth, reproduction and fecundity and age composition are described.INTRODUCTIONIn a trawling survey of the bottom-living fish of the Rockall Trough at depths from about 400 to 2900 m, 4 species of the family Moridae were sampled. Three species, Lepidion eques, Halargyreus johnsonii and Mora moro were distributed on the upper and mid slopes while a fourth species Antimora rostrata occurred on the lower slope and continental rise. Several different trawls were used to sample the fish populations of the slope and Gordon & Duncan (in the Press) have discussed the relative selectivity of each of these nets for sampling different species of fish. In many of the bathymetric zones fished morids were important both in terms of biomass and abundance. Some preliminary observations on aspects of the biology of Lepidion eques have been published (Gordon, 1979 a, b) and Mauchline & Gordon (1980, 1984) have described the diets of the morid fish from the Rockall Trough in some detail. In this paper other aspects of their biology will be described.
Notes on Shell-Depositions in Oysters: Note on the Chemical Composition of “Chalky” Deposits in Shells of O. edulis
Authors: Orton J. H. , Amirthalingam C. , Bull H. O. 
Published: May 2009

The observations recorded form preliminary studies which it is hoped will be useful in special investigations on the physiology of shell-depositions in oysters. The distribution of chalky shell-deposits on the internal faces of the valves in young and old O. edulis and O. angulata has been studied, and its average distribution determined in shells of O. edulis of jnedium age from West Mersea and the Fal Estuary.The distribution of this material in the shells of young O. edulis and in O. angulata is such that there can be little doubt that the function of the chalky deposit is to fill in rapidly grooves, hollows, and other spaces, which are inimical to efficient functioning in the changing needs of the individual.In O. edulis of medium age large deposits occur regularly in the shell adjacent to the exhalent chamber and smaller ones on the border of the shell in the region of the inhalent chamber. The hypothesis is advanced that these regular deposits can be explained in the same way as those more easily understood by assuming that in a high percentage of shells of medium age, the contour of the shell in the region of the exhalent chamber and other parts is such that rapid extension and contraction of the mantle cannot be effected; deposition of chalky shell-material modifies this contour of the shell with certainty in some cases, but hypothetically in others, so that the mantle can be extended and retracted with a maximum of efficiency.
The Fæcal Pellets of the Trochidæ
Authors: Moore Hillary B. 
Published: May 2009

FæecalPellets of the following species are described:—Gibbula cineraria (Linn.).G. umbilicalis (Da Costa).G. tumida (Montagu).G. magus (Linn.).Cantharus (Jujubinus) clelandi (Wood).Calliostoma zizyphinum (Linn.).
Growth in Length during the Transition from Larva to Adolescent in the Pilchard and Sprat
Authors: Ford E. 
Published: May 2009

Growth in length during the transition from larva to adolescent in the pilchard and sprat has been analysed, and simple straight-line equations deduced from observed data have been used to demonstrate how the different intervals along the dorsal and ventral surfaces of the body alter in length and proportion as development proceeds.In the herring, pilchard, and sprat at least one of the body-intervals remains for all practical purposes unaltered in length during the transition. In the herring there are two such intervals, namely, (1) the distance from the back of the brain along the dorsal surface to the insertion of the first dorsal fin-ray, and (2) the distance from the insertion of the pelvic fins along the ventral surface to the anus. In the pilchard and sprat one of the above two remains stationary, but the other increases in length; in the pilchard the fixed interval is the distance from the back of the brain to the first dorsal fin-ray, and in the sprat it is the distance from the pelvics to the anus.In the herring and pilchard the greater part of each unit of increase in the length of the body ventrally from the back of the head to the end of the caudal peduncle is added in front of the pelvic fins, whereas in the sprat this is added post-anally.
Studies of water movements and winds at various lightvessels II. At the Seven Stones Lightvessel near the Scilly Isles
Authors: Carruthers J. N. , Lawford A. L. , Veley V. F. C. , Gruning J. F. 
Published: May 2009

A review is given of the results obtained from upwards of 600 days of current measuring at the Seven Stones lightvessel during 1939–41. From the plotted observations, an attempt is made to deduce the association between the total daily water movement, irrespective of direction, the residual daily water movement or current, and the mean local residual wind.The average residual water movement over the whole period was 2½ m.p.d. towards east-south-east. Statements made by earlier authors regarding the water circulation in adjacent areas are examined, and reconciliations are suggested where they seem to conflict with this finding.An endeavour is made to correlate the wind and water movement mathematically.
The biology of Asterias rubens L. II. Parasitization of the gonads by the ciliate Orchitophrya stellarum Cépède
Authors: Vevers H. G. 
Published: May 2009

The parasitic astomatous holotrich ciliate, Orchitophrya stellarum Cépède, has been found in the testes of starfishes (Asterias rubens) in the Plymouth area. It was found only in starfishes from numerically rich and well-fed populations, which also showed large gonad growth. In such populations it occurred in up to 28% of the males during March-April 1947, and in lower percentages during the spring of the three following years. The parasite was never found in a geographically adjacent population containing smaller numbers of poorly fed starfishes. The parasite was found to be relatively more common in the testes of medium-sized starfishes than in those of large and small starfishes.Presence of the parasite causes a complete breakdown of all the germinal tissue of the testes, so that most of the infected starfishes suffer complete castration. This involution of the testicular tissue has been studied, and photomicrographs are given which show a number of stages in the process.
The respiration of some planktonic copepods
Authors: Raymont J. E. G. , Gauld D. T. 
Published: May 2009

The respiratory rates of four species of planktonic copepods were measured. In two of the species measurements were made with two copepodite stages, and with adult male and female specimens.The rate for Calanus finmarchicus Stage V at 17°C. was found to be 0·52 μl./cop./hr., a figure which agreed with previous measurements.For all the species and stages studied the respiratory rate was found to be closely proportional to the length to the power of 2·2.The relevance of such measurements to conditions in the sea is briefly discussed.
Muscle receptor organs in the Paguridae
Authors: Alexandrowicz J. S. 
Published: May 2009

In the dorsal wall of the abdomen in the Paguridae muscle receptor organs have been found similar to those in the Macrura. In each of the first to fifth abdominal segments there are two receptor units on each side. A receptor unit consists of a long thread-like muscle, and a nerve cell connected with this muscle and sending its axon towards the central nervous system. The muscles of each pair run close together in the layer of the dorsal (extensor) muscles, but are independent from the latter following a more or less different course.The nerve cells in each pair of muscle receptor organs are of two types. One of them has several very long distal processes expanding over one of the muscles. The other cell has one stout distal process giving off numerous but very short branches forming with their subdivisions a dense tuft of fibres terminating in the second muscle. The axons of the cells associate with one of the branches of motor nerves supplying the dorsal muscles and pass along these branches into the main nerve trunks of the respective segments.Each receptor organ is supplied by several nerve fibres coming from the central nervous system.
A Comparison of the Biology ofEchinus esculentusin different Habitats. Part III.
Authors: Moore Hilary B. 
Published: May 2009

1. Gonad examinations were made on monthly samples ofEchinus esculentusfrom Plymouth in 1934, 1935, and 1936.2. Spawning is from February–March to May, 50% spawning occurring at a temperature of 9.2–9–7° C. compared with 7.0—7.8° C. in the Isle of Man. There was a winter drop in gonad volume one year, but not the other.3. The nature, distribution and source of the pigments in the shell are discussed, and it is shown that pigment is found in quantity in the intestine only in the summer and autumn.4. The known facts with regard to the seasons of growth, spawning, etc., are brought together into a generalized diagram.