bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the origin and fate of flagellated gametes in multiple tests of discorbis (foraminifera)
Authors: Myers Earl H. 
Published: May 2009

It has long been presumed that the gametes of certain Foraminifera are flagellated; however, the lack of conclusive evidence as to the origin and fate of these flagellated gametes has made their existence problematical.In syzygous species of Discorbis the gametes are flagellated and the genetic relationship of these gametes is easily demonstrated, since gametogenesis, fertilization, and the development of two- and three-chambered multinucleate microspheric agamonts takes place within the excavated tests of two or more mononucleate megalospheric gamonts associated in syzygy.The life cycle of Discorbis herein described is in general agreement with the life cycle of Polystomella crispa proposed by J. J. Lister, and completes an interesting series of life cycles in which a progressive modification in behaviour and test morphology can be traced.Behaviour, ecology, and distribution of four syzygous species of Discorbis are discussed.Multiple tests of these syzygous species of Foraminifera can be found in most rock-bottomed tide pools that supports a growth of coralline algae. These sexual groups provide a sure source of material for the demonstration of flagellated gametes in the Foraminifera.
Notes on the life history of Sacculina carcini Thompson
Authors: Foxon G. E. H. 
Published: May 2009

The life history of Sacculina carcini parasitic on Carcinus maenas in the Clyde sea area is discussed and the breeding period and the time of the emergence of the young externa are indicated. The time and duration of the breeding season are compared both with what has been found at Plymouth and Roscoff for the same species of parasite on the same host crab, and also with what was found by Day (1935) who worked in the Mersey area on Sacculina carcini but parasitizing Portunus holsatus.The length of life of the Sacculina externa and their ultimate fate are discussed. It is shown that in male crabs which act as hosts the liability of the secondary sexual characters to modification is correlated with size.
Saccoglossus horstisp.n., an Enteropneust occurring in the Solent
Authors: Brambell F. W. Rogers , Goodhart C. B. 
Published: May 2009

1.S. horstioccurs on the Hampshire coast of the Solent near the mouth of the Lymington River, in glutinous grey mud associated withCorophium volutator.2. The species is distinguished by the following characters: coloration; dorsal and ventral grooves present on the proboscis throughout its length; collar forming a slight operculum posteriorly; ventral muscle bands of the trunk forming projecting ridges; rounded genital ridges present, the gonads beginning within 1 mm. of the collar; 100–140 pairs of gill slits; longitudinal muscle fibres of the proboscis arranged in nine or more concentric rings; ventral septum of the proboscis short; stomochord straight, with ventral diverticulum and wide lumen throughout; no dorsal glomerulus present; single proboscis pore on the left side; proboscis skeleton embracing half to two-thirds of the circumference of the buccal cavity and extending one-fourth to one-third of the length of the collar; four epidermal zones present in the collar; collar cavities completely separated; anterior extensions of the collar cavities extending into the neck of the proboscis; perihaemal cavities separate posteriorly but confluent in front of the level of the tips of the crura, and extending into the neck of the proboscis as far as the proboscis pore; neural keel well developed and in continuity with the epidermal nerve layer at intervals; no dorsal diverticulum of the buccal cavity; branchial epidermis characterized by the predominant intensely eosinophil glandular elements; tongues broader and projecting further into the lumen of the pharynx than the septa; epibranchial ridge formed by two convex ridges bounding a median groove; oesophagus divided into three regions; 4–8 intestinal pores; hepatic region of gut not sacculated and with an expanded lumen; gonads not lobed; oocytes attain a size of 0·23 × 0·17 mm.; yolk cells present in the ovaries.3. The probable identity of the specimen ofSaccoglossusfrom the French coast of the English Channel, recorded by Caullery & Mesnil (1916) asS. kowalevskyi, with this species is discussed.
Studies in the biochemistry of cirripede eggs. I. Changes in the general biochemical composition during development ofBalanus balanoidesandB. balanus
Authors: Barnes H. 
Published: May 2009

The biochemical composition–water, glucose, soluble and insoluble glycogen, protein and non-protein nitrogen, total lipid–of the eggs of Balanus balanoides and B. balanus has been determined during development.Preliminary analyses of the pigment content are reported.The changes in both species are similar; but they take place more rapidly in B. balanus with its shorter period of embryonic development.During development there is a net loss of all fractions; small increases of glucose and soluble nitrogen are, however, found at certain stages.The pigment is largely a chromolipid; during the early stages of development this increases, but is subsequently lost; astaxanthin is also present. The visual appearance is a poor guide to pigment content.The oxygen uptake of the eggs has been measured.There is a discrepancy between the oxygen uptake measured directly and that required to oxidize the substrate lost; the causes of this are discussed.The results are discussed relative to the habitats of the species.
On the Foraminiferida of the Plymouth region
Authors: Murray J. W. 
Published: May 2009

The seasonal changes in the foraminiferid populations along the Tamar-Eddy-stone profile have been shown for the winter, spring and summer of 1962. No single environmental factor appears to be wholly responsible for these changes but temperature is considered to be important. Variable salinities are of secondary importance in the Tamar. These seasonal changes have been compared with those observed at Christchurch and found to be different, presumably because of the different temperature and salinity conditions prevailing in the two estuaries.A qualitative assessment of the energy input of the environment from the nature of the deposited sediment has shown a good positive correlation between the distribution of the Miliolacea and a high-energy environment. All other superfamilies show a negative correlation with high energy, but the Cassidulinacea show a preference for a moderate-energy environment during the summer.Foraminiferids, found not to be very abundant in the Plymouth region, show a trend toward greater numerical abundance and greater diversity in passing out o t sea. The shortage of living foraminiferids is tentatively correlated with a restricted food supply.
Electrophoretic studies on blood proteins in an ecological series of isopod and amphipod species
Authors: Wieser Wolfgang 
Published: May 2009

An electrophoretic study of whole blood samples revealed the presence of haemocyanin and of various other proteins in the blood of fifteen species of marine and terrestrial amphipods and isopods.The amount of haemocyanin per 1 mm3of blood is independent of body weight over a range from 10 mg to 1 kg.Under laboratory conditions and during starvation the haemocyanin level of the blood is lowered as compared with freshly caught specimens.No relationship between moulting stage and haemocyanin content could be established in three oniscoid isopods, representingLigia, Oniscus, andPorcellio.In some species the densities of both haemocyanin and ‘slow proteins’ (i.e. proteins between starting line and haemocyanin) seem to vary in more or less the same direction, over at least part of the total range of variability. In the offshoreConilera, however, an indirect relationship seems to exist between these two protein fractions. This is reminiscent of the situation inMaia squinadodescribed by Zuckerkandl (1960).The slow protein fractions appear to play a number of roles in the species investigated. InConilerathey consist of various copper proteids (perhaps concerned with the synthesis of haemocyanin?), while in intertidal amphipods and some isopods they carry chromophilic groups that may be of importance in mechanisms of colour change. The colour of the blood of a given specimen ofOrchestia gammarellaandMarinogammarus marinusdepends on the amount of the faster moving, blue chromoproteid present in the blood. These chromoproteids are considered to be carotenoproteids.
On the fecundity of some gammarids
Authors: Cheng C. 
Published: May 2009

1. The number of species found in this investigation is six, of which four are marine and two brackish water.2. The mean value of the body weight and the fecundity varies with the species. The size of a species bears no relation whatever to the reproductive capacity.3. The fecundity is subject to seasonal variation, being generally higher in the spring than in the winter months.4. In general, a positive correlation exists between body weight and fecundity of the individuals of each species. This rule does not, however, apply to Gammarus duebeni, in which the fecundity appears to fall after reaching its maximum at the 19 mg. body-weight class.
The relation of Gammarus zaddachi Sexton to some other species of Gammarus occurring in fresh, estuarine and marine waters
Authors: Sexton E. W. 
Published: May 2009

Gammarus zaddachi is perhaps the most prolific and widespread of all the estuarine amphipods known to occur in northern Europe, and inhabiting, as it does, the low-salinity estuarine zone and adjacent coasts, it has come to be recognized in recent ecological work as a ‘salinity indicator’.Unfortunately, there has been constant confusion with the other common species of Gammarus, G. locusta, pulex, and duebeni, which has been greatly complicated by the difference in the appearance of zaddachi according as it lives in a freshwater or a saline habitat. It is shown that this difference is entirely due to the sensory equipment, the greater production of hairs in freshwater conditions, and that the structure of the two ‘forms’ is identical.The history of the species has been carried back as far as I have been able to trace it (1836) with the actual specimens, described in the different papers, and the more important of these papers are discussed. It will be seen that the material examined was derived from every country of northern Europe; from Russia, the White Sea, Crimea, and the Baltic, the coasts of Scandinavia, Germany, including the Hamburg water-supply, Denmark, the Netherlands, Great Britain and Ireland, and France as far up the Loire as Nantes.Detailed descriptions and figures of both forms of G. zaddachi are given; and finally, a comparison is made between the species most commonly confused with it, the Arctic species G. wilkitzkii being included because of a suggestion recently made that it might be, not a distinct species, but merely the Arctic form of zaddachi.
Further observations on changes in the bottom fauna of a fertilized sea loch
Authors: Raymont J. E. G. 
Published: May 2009

An account is given of the further changes in the bottom fauna of a fertilized sea loch (Loch Craiglin) from 1944 to 1947, and the results are compared with those obtained from 1942 to 1944.The bottom fauna density fell markedly during 1944, despite the addition of very large quantities of fertilizers. Unfavourable hydrographic conditions, especially low oxygen tensions, are considered to be responsible for the decrease.
Notes on the general biology ofTubularia LarynxEllis & Solander
Authors: Pyefinch K. A. , Downing F. S. 
Published: May 2009

A description is given of a number of observations ahd experiments on the larvae and colonies ofTubularia. The experimental material could best be referred to the speciesT. larynxEllis & Solander. Its characters are not wholly consistent with the diagnosis of this species, but the differences which exist are not great enough to warrant the erection of a new species.Liberation of the actinulae takes place more freely in darkness than in light, and there is evidence which suggests that it only occurs in still water or in weak currents.
On Manganese in Sea and Fresh Waters
Authors: Harvey H. W. 
Published: May 2009

A method of estimating the maximum quantity of manganese available to plants in sea and fresh waters is described.Samples of sea water collected off Plymouth in 1948 contained 0·7–1·0 mg. Mn/m.3in solution plus any particles soluble at pH 4·6. After storage and sedimentation of particulate matter, the quantity decreased to 0·0–0·25 mg./m.3Samples collected off the Isle of Man, an area with a rich summer population of flagellates, contained 2·0–2·6 mg./m.3The river Yealm, south Devon, on leaving Dartmoor contained 1 mg., and after passing through agricultural land 10 mg.\m.3Lakes and streams in the English Lake District contained 6–40 mg.\m.3The least fertile waters contained the least soluble manganese.
The Biology of Asterias Rubens L.: Growth And Reproduction
Authors: Vevers H. G. 
Published: May 2009

Considerable differences were found in the size compositions of populations of Asterias rubens off Plymouth. These differences were not correlated with age.Laboratory observations on rate of growth showed that well fed starfishes grow fast during summer and autumn and somewhat slower in winter. Poorly fed starfishes did not increase in size, but were able to survive for long periods with a minimum of food.
The Post-Larval Sand Eels (Ammodytidae) of the Celtic Sea and Plymouth Area
Authors: Corbin P. G. , Vati Vidya 
Published: May 2009

The post-larval sand-eels (Ammodytidae) occurring in the Celtic Sea and Plymouth area are identifiable as Ammodytes lanceolatus, A. tobianus, A. marinus (not previously recorded from the area), and a fourth species of Ammodytes, the adult of which, it is concluded, is not yet known.Adult Gymnammodytes semisquamatus (not previously recorded from the Plymouth area), the young of which are not yet known, increases the number of species in the area to five.
The reproduction and larval development of Nereis diversicolor O. F. Müller
Authors: Dales R. Phillips 
Published: May 2009

An account is given of the reproduction and development of the larva of N. diversicolor O. F. Miiller.In any one population the number of males was found not to exceed 10 %.The species is dioecious. Both sexes become green at maturity, but may be distinguished externally.Ripe oocytes, which vary between 200 and 250μ in diameter mature in a loose coelomic parenchyma, and are released by rupture of the body wall after its partial histolysis. Sperm is released through the nephridia, or possibly by rupture of the body wall as well. In the male histolysis occurs, but the coelomic parenchyma is transitory. Sperm matures in the form of coelomic sperm plates.
The Biology of The Small Planktonic Copepods of Plymouth
Authors: Digby P. S. B. 
Published: May 2009

The life histories of the small planktonic copepods of Plymouth were studied during 1947. The samples were taken at Station L4 with Harvey measuring nets, and are thus truly quantitative.The main species concerned were Pseudocalanus elongatus, Paracalanus parvus, Centropages typtcus, Temora longicornis, Acartia clausi, Oithona similis, O. nana, Oncaea venusta and Corycaeus anglicus.The species common in summer—all but the last three of the above—behaved in a very similar way, producing probably five generations in the course of the year, but differing from each other in the relative and absolute abundance of the different stages at different times of the year.
The Identification and Validity of Certain Species of Ascidians
Authors: Berrill N. J. 
Published: May 2009

There has existed in the past, and still does exist, considerable confusion both in the question of a satisfactory basis for the classification of ascidians and that of the validity of many species.The principal orders and families are fairly stereotyped, and confusion and divergent opinion is mainly confined to the internal classification of the various families. These differences have a twofold origin, in that classifications have been constructed by various authors on three distinct bases, and that it is very difficult to distinguish between structures which are similar through relationship and those which are similar through convergent or parallel development. Further difficulty arises from the fact that authors describing a new species with a view to fitting it into one particular classification, have often given insufficient details for its accurate inclusion in another scheme. There is also divergent opinion as to the correct nomenclature that should be employed, but with that this paper is not concerned.
Nitrate in the Sea. II
Authors: Harvey H. W. 
Published: May 2009

1. Observations made subsequent to December, 1925, confirm the conclusion that the nitrates in the water of the English Channel, twenty-two miles south-west of Plymouth, are almost entirely utilised by phytoplankton in the summer, and are reformed in early autumn at a greater rate than they are utilised.2. Movements of the water masses are shown to affect the quantity of nutrient salts available for phytoplankton in the waters immediately north of Ushant.3. The effect of land drainage on the quantity of nitrate in the sea is not apparent beyond a few miles to seaward from Plymouth Sound, being masked by the nitrate which is regenerated from dead marine organisms.4. The nitrate in the river and estuarine waters entering Plymouth Sound is nearly all utilised by plants in the rivers and estuaries themselves before reaching the open sea during summer.
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.