bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the biology of Crangon allmani Kinahan in Northumberland Waters
Authors: Allen J. A. 
Published: May 2009

Since November 1954, the natant epifauna in depths greater than 20 fm. off the Northumberland coast has been sampled at a number of stations with the object of obtaining information on its constitution and fluctuations. The survey has been limited to those species caught with a net of f in. mesh. Seasonal and yearly fluctuations in this fauna must have a considerable effect on the inshore fisheries, for these animals form an important part of the food of marketable fish, yet, this fauna has never beensubject to a detailed analysis over a number of years.Samples have been taken as regularly as weather and other laboratory commitments have allowed. In practice this has been of the order of one sample each month, butat times sampling has been more frequent than this (Table 8). Although sampling is being continued, the material collected so far gives much information on the epifaunaas a whole and the biology of the constituent natant Crustacea and Mollusca.
Exchanges of water between the English and Bristol Channels around Lands End
Authors: Cooper L. H. N. 
Published: May 2009

An understanding of the oceanography of the Celtic Sea requires anunder-standing of the exchanges of water around four headlands, Ushant, Lands End, St Davids Head and Carnsore Point. As a sequel to the study on the flow past Ushant already presented (Cooper, 1960b), this paper and the following one by Cooper, Lawford & Veley are attempts to achieve a better understanding of the exchanges around Lands End andin the neighbourhood of the Scilly Isles (Fig. 1).Matthews (1914, p. 20) said: 'The charts published in this report show that the saltest water enters the Irish area between Lands End and the Scilly Islands, and detailed observations made along this line on several cruises at intervals of from half a mile to one mile onthe Marine Biological Association's steamers have shown that the axis of highest salinity lies midway between the Longships Rock and the Seven Stones Lightship, that is, at a distance of only a few miles off Lands End. This current of salt warm water is derived from a current which has already entered the English Channel from a southwesterly direction, and has in part turned northwards and north-westwards to escape into the Irish Channel. It is practically certain that this water has come from the mouth of the English Channel and not directly from the open sea because further westwards a great area of lower surface salinity stretches southwards across the fairway and prevents any such direct current.' Harvey (1925, fig. 19) accepted Matthews' interpretation and later (1929) from a study of geopotential topographies deduced that a residual current ran between Lands End and the Scillies in June 1924 in a N.N.E. applies more nearly in the passage itself..
Manganese and the Growth of Phytoplankton
Authors: Harvey H. W. 
Published: May 2009

Inshore water collected near Plymouth during the late summer and autumn of 1945, after enrichment with nitrate, phosphate and iron, did not support continued growth of a species of Chlamydomonas, of Chlorella, of a Cryptomonad and of two species of Chrysomonads.The addition of 0-5-2-0 mg. Mn" or Mnv/m.3 allowed vigorous growth and the production of heavy crops. The effect on Chlamydomonas of adding as little as o-i mg./m.3 was apparent.The growth of Coscinodiscus excentricus varied in waters collected from inshore and from offshore which had been similarly enriched with N, P and Fe. The addition of manganese had only a minor effect.The addition of other microelements to inshore waters enriched with N, P, Fe and Mn did not affect growth rate of Chlamydomonas. Manganese starvation led to the production of small Chlamydomonas cells.Manganese starvation caused a resting condition or lag period in Chlorella. A supply of manganese alone was insufficient for recovery; a period of illumination was also required for internal changes to take place before logarithmic growth was resumed.The addition of manganese was effective when either nitrate or ammonium was supplied as source of nitrogen, in dim, bright, continuous, or discontinuous illumination.Metabolic products which leached out of the cells into the water during the growth of both Chlorella sp. and of Nitzschia closterium acted as a growth stimulant.Manganese at great dilution is rapidly 'collected' from solution by Chlorella. During growth this alga abstracts a material proportion from water containing 5 mg. Mn/m.3Using Chlamydomonas as 'analyst', it was found that added organic detritus, or the corpses of marine bacteria, adsorbed a material proportion of the manganese in sea water containing 1-2 mg. Mn/m.3
The Biology ofCrangon VulgarisL. in the Bristol Channel and Severn Estuary
Authors: Lloyd A. J. , Yonge C. M. 
Published: May 2009

Collections of some 22,000 female and 6000 male Crangon vulgaris were made throughout the year from the shrimp fisheries of the Severn Estuary and Bristol Channel. All animals were measured.The habits of the species are described; it can withstand a wide range of temperature but, though euryhaline, resembles other Decapoda in the inability to withstand low salinity combined with low temperature.Osmo-regulation is apparently largely inhibited at low temperatures and to a greater extent in the males than the females.Growth rate decreases with increasing age; in the female there is no increase in length when moulting from the ' neuter' to the egg-carrying intermoult. The duration of this intermoult, if spawning is successful, is about double that of the normal intermoult under the same temperature conditions. Growth almost ceases in the winter.Secondary sexual characters are described, especially the differences between the endopodites of the pleopods in the two sexes.Females become mature at a minimum length of 45 mm. in the Channel and seldom less than 50 mm. in the Estuary. The effect of the female sexual cycle on the size of the ovary and the form of the pleopods is described. The process of copulation is described; it can occur in the brackish waters of the estuary. Egg-laying always follows within two days of moulting into the egg-carrying condition but eggs are not retained if copulation has not occurred.The females lie on their sides during the act of spawning and the eggs are firmly attached within thirty minutes to the egg-carrying setae on the basipodites of the first to fourth pair of pleopods, then to those on the endopodite of the first pleopod, finally to those on the coxopodites of the last two pairs of pereiopods.
Notes on the Bionomics of the Tube Building Amphipod,Leptocheirus PilosusZaddach
Authors: Goodhart C. B. 
Published: May 2009

A study made of the adaptations to tubicolous life found in the small brackish water Photid Amphipod, Leptocheirus pilosus Zaddach, revealed several interesting points.The presence of cement glands in many amphipods has been recognized by several previous authors. In L. pilosus these glands are found mainly in the upper joints of the first two pairs of peraeopods, opening to the exterior through a common duct in the claw. Unicellular glands are also found all over the body, particularly on the coxal plates.
On the Nematocysts of Hydromedusae. II
Authors: Russell F. S. 
Published: May 2009

The nematocysts of the three species of Leptomedusae, Aequorea forskalea, A. vitrina, and A. pensilis, and of the two siphonophores Agalma elegans and Velella velella are described.The specific characters of the three species of Aequorea are discussed and it is shown that A. pensilis is probably the same species as A. macrodactyla
On the Growth and Feeding of Young Herring in the Clyde
Authors: Marshall S. M. , Nicholls A. G. , Orr A. P. 
Published: May 2009

Two groups of young herring are found in the Clyde. One, the offshore group, has been identified as Clyde spring-spawned herring; the other, the inshore type, is of unknown origin. The former were caught only occasionally, the latter at fairly regular intervals during their first year.The two groups are distinguished by differences in size and identified as belonging to different races by vertebral counts. There was no intermixture.The offshore herring which metamorphosed at the end of May when 40-50 mm. long, reached a length of 90-100 mm. in winter. The inshore fish which were about 50 mm. long in May reached a length of about 130 mm. in winter.
The Swimming and Burrowing Habits of Some Species of the Amphipod Genus Bathyporeia
Authors: Watkin E. Emrys 
Published: May 2009

The swimming and burrowing habits of four species of the genus Bathyporeia have been examined and shown to be alike, and similar to B. robertsoni as described by Schellenberg.Swimming is effected by the pleopods working in a metachronal rhythm, drawing water along a ventral groove formed by the coxal plates of the second peraeopods and the expanded bases of peraeopods 3, 4 and 5.The main water current enters anteriorly between the second gnathopods and is filtered by a series of feathered bristles borne on the basis of this appendage; a subsidiary current enters between the second and third peraeopods.Burrowing is effected mainly by the sweeping action of the second gnathopods and first two pairs of peraeopods, aided by the first and second uropods as soon as they can obtain a purchase on the sand. The adaptation of these three pairs of appendages to burrowing is explained.
The Distribution ofGammarusSpecies in Estuaries. Part I
Authors: Spooner G. M. 
Published: May 2009

The work of which an account is here given was largely carried out from the autumn of 1937 to the spring of 1940, when it was interrupted by the war. In taking it up again (in July 1945) while, facilities for field work are still limited, the author feels it useful to publish results as they stand and indicate where further work is considered advisable.In examinations of the free-swimming bottom fauna of the Tamar and other estuaries, attention was inevitably drawn to the populations ofGammarusspecies, which make up the greater bulk of it. Before quantitative observations were planned, some interesting points came to light with regard to the qualitative composition of populations. This aspect lent itself more readily to study and, though byno means a new field for exploration, soon proved worth examining ingreater detail than previous workers had attempted.The broad fact of a replacement of oneGammarusspecies by another in passing up an estuary was well enough known, though exact knowledge for the British Isles only starts from the time whenG. zaddachiSexton was recognized as a regular member of the upper estuarine fauna of the Tay (Bassindale, 1933; Alexander, Southgate & Bassindale, 1935) and of the Deben (Serventy, 1935). This species proved to be the main brackish-water species overlapping with the marineG. locusta(L.) near the seaward end, and with the fresh-waterG. pulex(L.) at the river end (or ‘head’) of the estuary. The status in estuaries of two other brackish-water species,G. duebeniLillj. and G.chevreuxiSexton, remained obscure.
The Spawning of Mackerel, Scomber Scombrus L., and Pilchard, Clupea Pilchardus Walbaum, in the Celtic Sea in 1937–39
Authors: Corbin P. G. 
Published: May 2009

The distributions of mackerel eggs and young stages, pilchard eggs, the siphonophore Muggiaea atlantica and the chaetognaths Sagitta elegans, S. setosa, S. serratodentata and 5. lyra in the Celtic Sea in March 1939, April, May-June 1937, 1938 and 1939 and July 1937 and 1938 are described, together with notes on the hydrological conditions in April 1937, 1938 and 1939, May-June 1939 and July 1938.Mackerel spawning started in mid-March, rapidly reached a maximum in mid-April, declined gradually through May and June and was very slight at the end of July.The changes in intensity of spawning are accompanied by a continuous shift eastward and slightly northward of the locus of spawning. In March spawning occurred in a small area at the western edge of the Continental Shelf only. In mid-April it was spread over the greater part of the Celtic Sea, with the main activity concentrated in two centres—to the south of Ireland and to the west of the mouth of the English Channel. By May-June it had shifted farther to the east and occupied the central area of the Celtic Sea. In July there was no spawning to the westward of the Scilly Isles.The spawning area of the mackerel appears to be confined to the shallow waters over the Continental Shelf.No mackerel young stages were found in March. Small numbers occurred in April (maximum 174). They were abundant in May-June (maximum 8239), and very scarce in July (maximum 20).The distribution of young stages closely follows the movement of spawning during the season.
The Preservation of Fishing Nets, Trawl Twines and Fibre Robes for Use in Sea Water
Authors: Atkins W. R. G. , Warren F. J. 
Published: May 2009

Manila ropes and trawl twines, and cotton nets, have been immersed in clean sea water for periods up to 14 months, some with alternate wetting and drying, some wet all the time, but in both cases accompanied by storage in air after immersion. All the untreated specimens perished, but the 700 lb. manila ropes retained at least 40% of the original tensile strength.in every case in which a copper soap had been included in the treatment. A previous treatment with cutch is a considerable advantage as shown by the 500 lb. manila ropes and trawl twines, though cutch alone is worthless. Coal tar distillates after cutch are, however, more useful than when used alone, and their mixture with copper soaps gives excellent results. Cutch fixed with bichromate gives tolerably good preservation on nets up to 6 months, but is a poor preservative for trawl twines and ropes which are expected to have a long life. The choice of the copper soap used depends upon the material to be preserved. Naphthenate is the most soluble and penetrates thick ropes excellently; on fine nets it leaches out easily. Oleate is cheaper, but its penetration is less; it does very well with tar on twines and nets. Resinate is the least soluble, but is useful with creosote oil or tar. On account of their greasy nature naphthenate and oleate act as lubricants in ropes.Immersion tests on other preservatives, kindly suggested by Dr S. G. Barker, are to be begun.
A Note on the Changes in Water Content of the Lobster (Homarus Vulgaris M.-EDW.) During Moult
Authors: Lowndes A. G. , Panikkar N. K. 
Published: May 2009

One of the lobsters kept in the tanks of the Plymouth Laboratory moulted on the night of 2 0 August 1940. This opportunity was taken to examine the changes in water content and osmotic pressure of the freshly moulted as compared with unmoulted lobsters. Though only one recently moulted individual has been examined, the results seem to be worthy of note since so far as we are aware no data are available on the subject in regard to Homarus. The biology of moulting among lobsters has received the attention of many investigators (vide Herrick (1895) and Drach (1939) for summary and literature).The water content was determined by distilling the fresh lobster together with a known weight of sea water under xylol. This method is a modification of that of Dean and Stark which one of us (A. G. L.) has tried on a number of animals and found to give accurate results. The density was estimated by a modification of a method previously described (Lowndes, 1938). Osmotic pressure of blood and the external medium were measured by Baldes's (1934) modification of the Hill thermoelectric technique, as employed by one of us (N. K. P.) in the study of prawns and other crustaceans. The water content of the moulted skin was calculated from its dry weight taken after dehydrating in a hot air oven for 48 hr. at 105° C. Osmotic pressure was measured 17±6 hr. after moult; density and water content after 34±6hr. The temperature of sea water at which the density was estimated was 17° C.
Notes on Certain Aspects of the Biology of Cumopsis Goodsiri (Van Beneden) and Some Other Cumaceans in Relation to their Environment
Authors: Dixon Audrey Y. 
Published: May 2009

The breathing, feeding, swimming, burrowing and cleaning habits of Cumopsis goodsiri are discussed.Cumopsis has compact respiratory chambers. The inspiratory current enters each gill chamber posteriorly at the base of the third maxillipede, and the expiratory current leaves anteriorly through the siphons which pass through the pseudorostral chamber. The inspiratory current is filtered from all suspended particles by a sieve placed at the mouth of the respiratory funnel, which is formed by the depression of the third maxillipede away from the body. The size of the spaces in the mesh of this sieve probably determines the grade of the substratum in which the animal can live.Cumopsis feeds on micro-organisms which it cleans off sand grains and other small objects. These are collected by the first peraeopods, held in position by the third maxillipedes, and cleaned by the first and second maxillipedes. The food is then passed on to the maxillae, maxillules and mandibles and finally enters the mouth. All these appendages are suitably armed to perform their respective functions.Use is made of the last four pairs of peraeopods in burrowing and Cumopsis will only burrow into a sandy substratum. Swimming is accomplished in three different ways: (a) by flexures of the abdomen, (b) by paddle-like movements of the exopodite of the first peraeopod, and (c) in adult males by the abdominal pleopods.The body is cleaned by the uropods. Their general rough surface and flexibility is very important. The uropod armature seems to add efficiency to the cleaning movements in the adult animals, particularly in the males.The size of the soil particle is vitally important in the distribution of the Cumacea. It determines whether the animals breathe properly. There is also probably a close association between the soil grade and distribution of soil micro-organisms upon which they feed. As a result they refuse to burrow into a soil grade which is unfavourable.
Ichthyosporidium Hoferi (Plehn & Mulsow, 1911), An Internal Fungoid Parasite of the Mackerel
Authors: Sproston Nora G. 
Published: May 2009

A fungus has been found causing a fatal disease among mackerel in British waters, and a very high rate of infection has been maintained for over three years. It is spread throughout the viscera by the circulation, being particularly common in the kidney and spleen: it is very rare in the muscles and has never been found in the gonads or central nervous system of these fish.Growth of the aseptate, sparsely branched hyphae is usually radial, from one of three types of central body. The length and thickness of the hyphae varies according to the density of the infected tissue and the degree of resistance which is set up. Connective tissue capsules are laid down round spores and hyphal bodies, occluding the small vessels or capillaries in which they become lodged. Growth of the parasite stretches the capsule, which may become a tubular gallery containing many growth stages. This may effectively seal the parasites which then degenerate; or, more usually, the strong proteolytic enzymes secreted by the advancing hyphae perforate it, and proceed to convert the whole organ into a necrotic mass in which hyphae grow to great lengths. There is always a tendency for hyphal walls to collapse behind the outgrowing hyphae, giving the appearance of hair-like threads with swollen ends.Any of the following developments may occur, apparently on any hypha, in tissue undergoing necrosis: (1) Bunches of large elongated chlamydospores, with a very hard exospore and a thick (?) gelatinous endospore—a germination pore is present; (2) Single dome-shaped conidia (like those of Entomophthoraceae); (3) Hyphal bodies of various shapes, either growing at once where they become lodged or becoming rounded and encysted—these may subdivide irregularly, each spherule having a separate cyst; (4) Branched conidiophores with rounded tips which contain endo-conidia—liberated as minute amoeboid bodies into the blood vessels; (5) Simple clavate sporangia from the ends of unbranched hyphae, also containing endo-conidia; (6) Hyphal fusions of numerous kinds, immediately proceeding to further outgrowths of similar hyphae; (7) ‘Spores produced by hyphal fusion’: fusion of two hyphae followed by the participation of neighbouring hyphae which also contribute to form the outer, resistant, rugose wall.
A New Apparatus for the Collection of Bottom Plankton
Authors: Wickstead J. 
Published: May 2009

A description is given of a new type of apparatus designed to sample plankton from the immediate vicinity of the sea bottom, and purely from this region. Details of the construction are given and the relative merits of the design are briefly discussed.It could be used for quantitative hauls.A small additional net serves to sample the smaller benthic fauna at the same time as bottom plankton is being sampled.
Observations on the Breeding and Settlement ofMytilus Edulis(L.) in British Waters
Authors: Chipperfield P. N. J. 
Published: May 2009

During 1946 and 1947, regular samples ofMytilus edulisfrom a number of localities ontheBritish coasts, including Conway, Brancaster and Liverpool, were examined for gonad conditionand spawning. For each sample, the mean stage of gonad development was computed. The criteria employed in distinguishing the stages of gonad development are described.Ripening of the gonads takes place within a few weeks of the onset of spawning, in general commencing when the sea temperature has risen above 7–0° C. There appears to be no correlation between nutritional condition and ripening of the gonads, or subsequent spawning.In all localities and in each year in which observations were made spawning occurred in late spring (mid-April to the end of May) and in most areas lasted for a short period only (2–4 weeks). At Brixham, in 1949 and 1950, the duration of the spawning period was longer (4-6 weeks). In most cases, 70–80% of the mature population spawned during the first 7–10 days of the breeding period. No evidence of periodic spawning was obtained.In all cases, spawning commenced in a period during which the mean temperature to which the mussels were exposed was rising from c. 9–5° C. to 11–12–5° C. In most cases, the onset of spawning was coincident with a period of spring tides, and of predominantly bright sunny weather. The initial rate of spawning appears to be directly related to the rate of increase in mean temperature to which the mussels are exposed.After spawning, mussels enter into a ‘neuter’ or ‘resting spent’ stage in which all traces of sexuality are lost.
The Larvae of the Spatangidae
Authors: Rees C. B. 
Published: May 2009

An account is given of the general structure of the body skeleton of the spatangid larva. A considerable change occurs in the skeleton as the larva increases in size, some parts being absorbed and new parts appearing. Of particular interest is the replacement of the anterior transverse rod by the ventral horizontal rod.The skeletons of larvae, young stages to late stages, ofEchinocardium cordatum, E. flavescens, Spatangus purpureus and Brissopsis lyriferaare described. The larvae ofEchinocardium and Spatangusare, in essentials, very similar; that of Brissopsis differs greatly from them. A striking difference is that in Brissopsis the ventral horizontal rod arises from the postoral arm and anterior to the anterior transverse rod, in the other two genera it arises from the body rod posterior to the anterior transverse rod.The replacement of the anterior transverse rod by a ventral horizontal rod is probably normal in clypeastroid larvae also.