bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Occurrence of Diadumene Cincta T. A. Stephenson in the River Roach, Essex
Authors: Rawlinson Ruth 
Published: May 2009

Several small anemones resembling Metridium dianthus were collected from the River Roach and sent to me in the summer of 1934. A careful examination proved them to be Diadumene cincta which was first recorded from Plymouth. T. A. Stephenson (1, 1925, p. 880) described both an orange and a fawn variety of this species, the former from the Breakwater and the latter from the Pier, Plymouth. The Roach anemone agrees with the Plymouth one in all its more important habits and its external and internal characters. It would appear that the specimens of D. cincta from the New England Creek, Essex, recorded by T. A. Stephenson (2, 1935) since this account was first written, may have been derived from this river.The anemones were dredged in abundance from the River Roach attached to living and dead shells of Ostrea and Mytilus and to Alcyonidium and Halichondria. All (about thirty) which I have seen were small, the diameter of the base averaging 0.6 cm. and the disc 1.5 cm. They were orange, but some were pale while others were more deeply coloured. No fawn ones have as yet been found in this locality.The scapus wall is thin, translucent with a bluish caste and with the mesenterial insertions showing through. The cinclides are evident as distinct dull purple-grey spots, each with a central depression clearly visible under a hand lens. The tentacles are the same colour but paler than the scapus. They are usually uniformly coloured but in some specimens there are two faint bluish lines running along their upper surface and, in one individual, there was a pair of short dashes at their bases instead of these lines.
Additions to the Plymouth Marine Fauna (1931) in the Crustacean OrdersTanaidacea, IsopodaandAmphipoda
Authors: Crawford G. I. 
Published: May 2009

Thislist contains 2 species of Tanaidacea, 6 of Isopodaand 28 of Amphipoda. These were all collected by myself in 1934–5, with the exception of 3 species of Amphipoda, which have not been entered in the Plymouth list although accounts of their capture at Plymouth have been published. These areEusirus longipesBoeck, recorded by Hunt (1924);Gammarellus angulosus(Fabr.), by Kitching, Macan and Gilson (1934); andGammarus zaddachiSexton, by Serventy (1935).The list is drawn up in the systematic order adopted in Plymouth Marine Fauna (1931), with a reference to a good illustration of each species. The dates and circumstances of capture are stated, and when a species has already been recorded from off the coasts of Devon and Cornwall by Norman and Scott (1906) a note to that effect has been made. The distribution is not stated, since recent accounts of the distribution of every species are available in the following works:Tanaidacea and Isopoda: Nierstrasz and Stekhoven, 1930 (except forSynisoma acuminatana, q.v.).Amphipoda: Chevreux and Fage (1925) or Stephensen (1929).All the Amphipod species in this list are included in one or other of these publications, and almost all in both.Every species has been referred to a specialist for identification. Tanaidacea andEurydice truncataandGnathia oxyurœato J. H. Schuurmans Stekhoven of Utrecht; the other Isopoda to Prof. W. M. Tattersall of Cardiff; the Amphipoda to Dr. K. Stephensen of Copenhagen, exceptingGammarus zaddachiSexton, which Mrs. Sexton herself has named.
Part III. The Zooplankton-Herring Correlations in the Scottish Fisheries
Authors: Henderson G. T. D. 
Published: May 2009

(1) In the Scottish Eastern and Western Fisheries 459 Plankton Indicator samples have been analysed and the results studied for evidence of correlations between the zooplankton and the 533 associated catches of herring. (See Part IV for the phytoplankton correlations.)(2) In the Eastern Fishery, 1930-33, out of twenty half-month areaperiods considered of primary value, fifteen show positive Calanus-Herring correlations and five negative. The area-periods of secondary value confirm this three to one ratio, there being eight positive and three negative results indicated. (A three to one ratio was also found in the Shields Fishery. Part II.)(3) An attempt to estimate the commercial value of the Indicator, when used to locate the richer Calanus waters, shows that if in each period (1931-33) the fishing had taken place in the richer Calanus waters a gain of 24-5 i 7 -7 % over the catch secured by fishing at random should have resulted.
The Ovary as an Indicator of the Spawning Period in Fishes
Authors: Hickling C. F. , Rutenberg E. 
Published: May 2009

Accounts of the ovarian development of the eggs of fishes have been given by Kisselevitch (1923). Mayenne (1927), and recently by Hickling (1930) and Raitt (1933). They have concluded that in the ovary of the adult fish there is a general egg-stock of small eggs, yolkless and transparent in fresh material, and with deeply staining cytoplasm in fixed and stained material. From this egg-stock a quota is withdrawn each year to be matured and finally spawned, and to this egg-stock a fresh batch is added each year by the development of oocytes present beneath the surface of the ovigerous lamellæ, the minimum period of development being two seasons.It has occurred to us that measurements of the diameters of eggs, in ovaries well advanced towards spawning, may give evidence of the duration of spawning in a fish of which the spawning habits are unknown. For where the spawning period is short and definite, the batch of transparent yolkless small eggs, destined to mature and be spawned, will be withdrawn from the general egg-stock in a single group, sharply distinguishable, at least in the later stages of maturation, from the stock of small eggs from which it was derived. But when the spawning period is long and indefinite, the withdrawal of eggs from the egg-stock, to undergo maturation, will be a continuous process, and there will be no sharp separation between the general egg-stock and the maturing eggs. These will pass continuously one into the other. We have tested this hypothesis with four species of fish of known spawning habits.
A Summary of the Work on the AmphipodGammarus CheureuxiSexton Carried out at the Plymouth Laboratory (1912–1936)
Authors: Sexton E. W. , Clark A. R. 
Published: May 2009

Thework began in June, 1912, simply as a study of the life-history of some of our common amphipods. The genus Gammarus was chosen, because of the number and the wide distribution of its species in the neighbourhood. Seven of these species, all black-eyed, from marine, estuarine, brackish and fresh waters, were kept in the laboratory for investigation until the first red-eyed specimens were discovered in one of the brackish species, later described asGammarus chevreuxi(see p. 360). Since the manner in which these red-eyed individuals occurred raised points of considerable interest, it was decided to confine investigation toG. chevreuxi, and a series of experiments was started. The different variations involving both the structure and the pigmentation of the body and of the eyes appeared from time to time, some behaving as simple mendelian characters and attributable to the presence of a single recessive gene, others with a more problematical hereditary basis. These variations have been recorded as they occurred (see bibliography). For ten years, no second mutation appeared, although frequent dredgings were made and the animals thus obtained were kept for several generations in laboratory conditions. Because of this apparent stability of character the wild Gammarus was regarded as a homogeneous population until, in 1922, it became increasingly evident that the results showing in the laboratory cultures could only be explained on the supposition that many recessive factors must be present in the natural conditions.The evidence steadily accumulated, but direct proof was very difficult to obtain partly because (as we found in our experience with the cultures) the recessive types are often less viable than the normal, and therefore probably less able to withstand the competition in the wild, and partly perhaps because we had no criteria by which to assess the influence of the laboratory conditions (changes of temperature, food, salinity, pressure, etc.) on the constitution of the Gammarus, and so could not decide whether a variation was caused by the inherent action of the recessive genes, or by the untoward environment producing a change in the action of the normal genes.
On The Biology Of Glossus Humanus (L.) (Isocardia Cor Lam.)
Authors: Owen G. 
Published: May 2009

Glossus humanus (L.) (Isocardia cor Lam.), a large marine eulamellibranch, occurs in deep water in soft muddy substrates. Restriction of the species to a soft substrate is probably correlated with the inflated form of the shell, the weak musculature of the foot, and the poor elastic properties of the ligament.Growth of the mantle/shell is the resultant of radial, transverse and tangential components, the normal axis being a turbinate spiral. The anterior region of the ligament is progressively split during growth owing to the displacement posteriorly of the secreting surfaces. The relationships of the valves, ligament and mantle isthmus are discussed.The deeply plicated ctenidia are specialized for dealing with large volumes of water containing little suspended material.The anatomy and functioning of the stomach is described in detail. There is a complex ciliated mechanism selecting particles on the basis of size. Such a mechanism, it is suggested, must be associated with intracellular digestion. The flap-like major typhlosole prevents material carried by the intestinal groove from returning to the circulation within the stomach, while the retention of an isolated opening for the left pouch is probably correlated with the need for firm fixation of the gastric shield.Spawning occurs at the end of September.
Some Experiments on the Function of the Pericardial Organs in Crustacea
Authors: Alexandrowicz J. S. , Carlisle D. B. 
Published: May 2009

Experiments with isolated hearts of various Crustacea (Cancer pagurus,Maia squinado,Homarus vulgaris,Squilla mantis) were performed in order to test the postulated secretory function of the pericardial organs (nerve trunks of unusual structure lying in the pericardial cavity). Tests were made with extracts of these elements added to the fluid perfusing isolated hearts.InCancer,HomarusandSquillathe extracts caused a distinct increase in amplitude and frequency of the heart beat, and their effect proved to be very similar to that produced by adrenaline and noradrenaline tested on the same hearts. InMaiathe extracts produced an increase in amplitude and decrease in frequency of the heart beat.Extracts of the pericardial organs ofCancer pagurusgave the fluorescence reaction characteristic of adrenaline and related compounds. Blood taken from the pericardial cavity gave the same reaction, but that taken from the leg arteries did not.It is assumed that the function of the pericardial organs in the Crustacea consists in liberating, through fine neuropile-like terminations of the nerve fibres, some hormone passing with the blood into the heart and producing on it a stimulating effect. There is certain evidence that the pericardial organs might release a second hormone having an inhibitory and perhaps also a stabilizing effect on the heart rhythm.
A New Dredge for Collecting Burrowing Animals
Authors: Forster G. R. 
Published: May 2009

The 'anchor-dredge' is a lightly built one-sided instrument designed to catch deep-burrowing animals. The depth to which it digs is dependent on the pull of the warp and not on the weight of the dredge.From a trawler, it is best to work the dredge from the forward gallows, and give it a 'tug' as the ship is moving astern.Comparative tests and direct underwater observations have shown that the anchor-dredge samples the in-fauna more efficiently than do either large rectangular and oval dredges, or the conical dredge.A description and plan is given of a larger model, designed for use from a 6o-ft. or 90-ft. ship.
The Respiration of some Planktonic copepods II. The Effect Of Temperature
Authors: Gauld D. T. , Raymont J. E. G. 
Published: May 2009

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.
The Preservation of Fishing Nets, Trawl Twines and Fibre Ropes for Use in Sea Water
Authors: Atkins W. R. G. , Warren F. J. 
Published: May 2009

A trade waterproofing of sisal rope had still some effect after 3 days in sea water, the untreated being four-fifths saturated in 1 hr.Treating manila, sisal and coir rope with Cuprinol or tar increases the wet weight at the most only slightly as less water is taken up than without preservative.Water equilibrium is not attained till long after the B.S.I, specification test period for waterproofing sisal rope, but some effect of waterproofing may be distinguished up to perhaps 3 days.On cotton netting copper naphthenate preservatives were most durable in a clean sea-water basin, but Dr Olie's method with cutch and ammoniacal copper sulphate ran them close and is cheaper. The best lasted 9 months as against untreated 5½ months.On trawl twines the British Columbia grade of Cuprinol, a proprietary mixture containing copper naphthenate, was the best of those tried, and the twines lasted 16 months as against almost 9 for untreated manila.On thin sisal rope six copper preparations are still under test.
Spontaneous Squirting of an Ascidian,Phalliusia MammillataCuvier
Authors: Graham Hoyle  
Published: May 2009

The previous work on spontaneous activity in ascidians is briefly reviewed: there is clear evidence for the existence of spontaneous contractions of the siphons of certain monascidians but no function has been ascribed to this activity.Phallnsia mammillataexhibits spontaneous contractions of its siphons at intervals of 6-9 min. over long periods in Plymouth tank sea water. The siphon contractions are synchronous. The frequency of the contractions may shift fairly quickly under constant conditions to a higher or lower rate which is usually twice or one half the normal rate.A method of recording the volume of water propelled by spontaneous activity is described. The method also records the ciliary through-current at the same time as the squirts.The frequency of the squirting is increased during a period of partial or complete starvation. It is reduced again by adding food cultures to the water.The physiological mechanisms involved in the spontaneous activity are investigated and comparisons are made with the spontaneous activity exhibited byMetridium senileandArenicola marina. It is finally suggested that the spontaneous squirting of certain ascidians is an integral part of their feeding mechanism.
Nervous Organs in the Pericardial Cavity of the Decapod Crustacea
Authors: Alexandrowicz J. S. 
Published: May 2009

In the pericardial cavity of the decapod Crustacea the nerve fibres end in characteristic neuropile-like networks which surround bundles of thicker fibres or spread over the pericardium wall and the heart ligaments. It is proposed to designate the whole system of these elements as 'pericardial organs'.The arrangement of the elements constituting the pericardial organs varies in different groups of the Decapoda. In the Brachyura the bundles of fibres surrounded by neuropiles form conspicuous trunks linked with each other; the main parts of these trunks are situated at the openings of the branchiocardiac veins into the pericardial cavity. In Eupagurus bernhardus two main trunks flank the heart giving off branches which spread in various directions and form at some places plexuses on the pericardium wall. In Leander serratus the pericardial organs are represented by several trunks running near the lateral wall of the pericardium in the dorsal direction and uniting by archshaped branches. In Homarus vulgaris there are four comparatively much shorter trunks situated at the lateral wall of the pericardial cavity, but plexuses of neuropile-like nerve fibres spread over large areas.The trunks of the pericardial organs are suspended in the pericardial cavity in such a position that they may be bathed on all sides by the blood passing from the gills. The plexuses extending over the membranes are situated in places also exposed to the blood stream. There is evidence indicating that the pericardial organs produce substances influencing the heart-rhythm. It is assumed that these substances are liberated into the blood by a process of neurosecretion occurring at the terminations of the nerves.
The Seasonal Cycle in the Cornish Pilchard, Sardina Pilchardus Walbaum
Authors: Hickling C. F. 
Published: May 2009

1. In the pilchard (Sardtha pilchardus Walbaum) of Cornwall there is a substantial seasonal variation in the mean weight of a fish of given length. The weight is highest in late autumn and early winter, and least at the end of winter and the early spring.2. These changes in weight are largely due to variations in the fat content of the fish, which are richest in fat at the beginning of the winter fast, and poorest at the end of it. But, especially among the larger fish, the 'residue', chiefly proteins, are drawn upon at the time of the exhaustion of the fat, and consequently at the time of minimum mean weight. The water and ash content show no seasonal variation, and therefore play no part in the observed seasonal variation in the mean weight of the entire fish.3. The gonads have their lowest mean weight in August, increase in weight slowly throughout the winter, and are at their maximum state of development from April to July. The spawning season, as deduced from these samples, is from March to September.4. The rate of feeding is greatest in the same months as the spawning months, namely, from April to July. From July to September the average weight of food per stomach decreases, probably not because the planktonic food is then less abundant, but because it is shared among a greater number offish. In October there is a rally in the rate of feeding, but from November to February or March is a period of fasting, when very little food is taken.5. The food of the pilchard is exclusively planktonic. In the spring, and again in the autumn, diatoms are abundant or even dominant in the food; in the summer, copepods and Crustacea are the chief items of food.
Vertebral Variation in Teleostean Fishes
Authors: Ford E. 
Published: May 2009

Since the publication of Heincke's classic treatise on the herring the counting of vertebrae has become a standard operation in the biometric analysis of samples of teleostean fishes taken at random from local populations. But while such routine counting has undoubtedly added greatly to our knowledge of the incidence and magnitude of vertebral variation in a number of economically important species, it has occasioned no little confliction of opinion as to the significance of this variation. Difficulties arising out of my own work on the herring at Plymouth have led me to make a general study of the teleostean backbone in as many species as possible, in an endeavour to learn more of the nature, extent and cause of vertebral variation. After examining over one hundred species, mostly from local waters, I have come to the conclusion that the subject presents a great and varied field of research which is at present but little explored. It would be idle to suggest, therefore, that the present paper should be considered as anything more than an introductory survey of the many problems awaiting detailed investigation. Even so, it may serve to indicate the scope and present position of the Plymouth studies, and prepare the way for fuller work in the future, both at Plymouth and elsewhere.I have received the greatest assistance from Mr L. S. Wisdom, Laboratory Attendant at the Plymouth Laboratory, whose skill in preparing skeletons for study, and keen interest in all matters relating to the research, I most gratefully acknowledge.
Oxidation-Reduction Potential in Sea Water
Authors: Cooper L. H. N. 
Published: May 2009

The activity of oxygen in sea water and standard oxygen electrode potentials at a range of temperatures have been computed.Accurate values for the thermodynamic ionic product of water, Kw, found by Harned & Hamer, have been applied to the calculation of the activity of hydroxyl ion in sea water from pH measurements.The activity of water in sea water has been computed from the lowering of the freezing-point.From these data the theoretical reversible oxidation-reduction potential of sea water has been calculated..Typical data for the irreversible potential in the pH range 1-8 have been derived from Hoar's results with which experimental determinations made by Dr Atkins agree. Thus the oxidation-reduction potential of sea water is controlled solely by the oxygen system.
The Preservation of Contractile Marine Animals in an Expanded Condition
Authors: Gohar H. A. F. 
Published: May 2009

The importance of killing contractile animals in an expanded condition cannot be over-estimated. A glance at the immense confusion and uncertainty which prevails in several branches of tropical marine invertebrates, and in particular the Coelenterata, will give a clear picture of the value of good preservation. Killing contractile animals in an expanded condition has always offered considerable difficulty. Several methods have been recommended for different animals, but it is often very difficult to choose the appropriate one, since animals belonging to one and the same group may behave quite differently towards any method. The writer, during his work for the last three years at the Marine Biological Station of the University of Cairo at Ghardaqa in the Red Sea, has taken great pains to preserve a variety of marine invertebrates as fully expanded as possible. Some of the successful results and the methods used are therefore given here.The commonest method for the present purpose is the use of narcotics. The most familiar of these are menthol, chloral hydrate, alcohol, magnesium sulphate and cocaine. Owing to the difficulty in obtaining cocaine it cannot be freely used for general purposes. Menthol enjoys a great reputation for narcotization which, in fact, it does not quite deserve. Although in some few cases it gave good results, yet in the majority it was quite unsatisfactory, as delicate animals begin to macerate before they are properly narcotized. It is generally applied in the crystal form and sprinkled on die surface of the water. Apparently its low solubility is responsible for a great many of its failures.