bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Buoyancy of the Cuttlefish,Sepia Officinalis(L.)
Authors: Denton E. J. , Gilpin-Brown J. B. 
Published: May 2009

The excess weight in sea water of the living tissues ofSepia officinalis(L.) is approximately balanced by the cuttlebone, which accounts for about 9·3% of the animal's volume. The density of cuttlebone varies around 0·6. The cuttlefish without its cuttlebone would be about 4% denser than sea water.The chambers of the cuttlebone are independent of one another but liquids and gases are free to move within any one chamber.Animals caught and studied fresh aboard ship exhibited a much less wide range of cuttlebone densities than those kept in an aquarium.Specimens kept in aquaria vary greatly in buoyancy. These variations result from changes in density of the cuttlebone.Cuttlebones differ not in the weight of dry matter per unit volume, which is always close to 38%, but in the amount of liquid they contain. A cuttlebone of density 0·7 contains about 30% liquid whereas a cuttlebone of density 0·5 contains about 10% liquid. The remainder of the cuttlebone contains gas, but this gas is at less than atmospheric pressure. The pressure of gas varies around 0·8 atmosphere. Within the duration of the experiments described here, the mass of gas per unit volume of bone remained almost constant whatever the bone's density. The pressure of gas is lower the less dense the cuttlebone. There can be no question of an evolution of gas expelling liquid from a bone when it becomes lighter. The constancy of the mass of gas within the cuttlebone is explained in terms of the slowness of diffusion of gases into the bone.
A Postlarva of an unknown Fish from the West Coast of Scotland
Authors: Russell F. S. 
Published: May 2009

While examining collections of young fish taken with a 2 m stramin net on the west coast of Scotland in 1975 for the unstaffnage Marine Research Laboratory of the Scottish Marine Biological Association I found two postlarvae unlike any I have seen before.These two specimens, both about 6.2 mm long, were taken on 31 July 1975 from the Tiree Passage between the Islands of Mull and Tiree, and from Bloody Bay on the south-west coast of Mull.
The Composition of Gas in the Chambers of the Cuttlebone of Sepia Officinalis
Authors: Denton E. J. , Taylor D. W. 
Published: May 2009

Gases from the chambers of the cuttlebone have been analysed. Their partial pressures were never higher than those expected in the tissues of the animals.In the older chambers the gas was about 97 % N2. The pressure of the gas in these chambers is always close to 0.8 atm.These results are in accord with the theory that the gases play an unimportant role in the mechanism of the cuttlebone and merely diffuse into spaces created by forces other than gas pressure.Observations have been made which can be used in studies of the life history and the rates of growth of cuttlefish in the Channel.
On a new medusa, Krampella dubia n.g., n.sp.
Authors: Russell F. S. 
Published: May 2009

In a collection made with a 2 m stramin ring trawl at 47°03′ N., 5° 47′ W. on 4 July 1956, with 800 fathoms of wire out, I have found a new species of medusa. This specimen is in a comparatively good state of preservation except that the stomach is badly damaged.The umbrella is hemispherical and the jelly is moderately thick. The form of the stomach cannot be described for certain. Parts of it are to be seen as narrow strips hanging down from the upper ends of three of the radial canals. One of these strips is continued for a short distance along the subumbrella surface towards the summit. It has the form of two short curtains with a space between them which leads into the radial canal. It thus seems quite possible that the stomach is i n fact an open cross with mouth lips extending along each arm as in Staurophora.
Vitamin A and carotenoids in certain invertebrates VI. Crustacea: Penaeidea
Authors: Fisher L. R. , Kon S. K. , Thompson S. Y. 
Published: May 2009

Vitamin A and carotenoids were measured in six species of Penaeidae and seven species of Sergestidae.Vitamin A was present in at least one sample of all species except Gennadas borealis at concentrations mostly of the same order as previously found in other Decapoda, but usually higher in the Sergestidae than in the Penaeidae.Carotenoids in the Penaeidae included astaxanthin and its esters, carotenes and xanthophylls, but only astaxanthin or its esters with occasional traces of xanthophylls were found in the Sergestidae.
Lernaeocera obtusa n.sp., a hitherto undescribed parasite of the haddock (Gadus aeglefinus L.)
Authors: Kabata Z. 
Published: May 2009

The fishes harbouring parasites of the genus Lernaeocera can be divided, according to the presence or absence of contact with the coastal waters, into ‘inshore’ and ‘offshore’ groups. According to literature, only L. branchialis occurs commonly on hosts in both groups. The difference between this and the remaining species of the genus is explained by the existence of two different species covered by the name L. branchialis. One of these species is parasitic on cod and whiting, the other on haddock. The two species have also different intermediate hosts (flounder and lemon sole respectively) and differ in morphology of the adult male and female and in the mode of attachment to the final host.Lernaeocera of whiting and cod is distributed mainly in the coastal area, while that from haddock extends over the whole of the North Sea. The former, but not the latter, is present outside the European continental shelf. All these differences lead to the conclusion that the two types represent two different species. The old name is retained for the parasite of cod and whiting. The parasite of haddock is the new species, to which the name Lernaeocera obtusa is given.
Sound production and stridulatory structures in hermit crabs of the genusTrizopagurus
Authors: Field Laurence H. , Evans Athale , Macmillan David L. 
Published: May 2009

The cheliped stridulatory structures are described forTrizopagurus strigimanus,T. melitai,T. tenebrarumandT. strigatus.Sound inT. strigimanusis produced during reciprocal flexion and extension of the carpo-propodite and mero-carpopodite joints of tightly apposed chelae. These underwater sounds occur as syllables, each of which is composed of damped pulses with a repetition rate of 36–303/s and a within-pulse frequency of 6–8 kHz. The maximum sound pressure level (peak to peak) 15 cm from the source was 24 dB re: 1 Pa.The gastropod shells inhabited byT. strigimanushad a weak effect (5% pressure difference) on directional radiation of sound in the near field (5 cm) and no effect beyond 20 cm from the crabs.Cavity resonance of the shells was predicted from a mathematical model, but only appeared important at a fundamental frequency of about 4 kHz, when tested in animals partially removed from their shells. A more significant effect was low-frequency vibration (100–300 Hz) imparted to the shells through direct contact by the hermit crab inhabitants.Behavioural experiments suggested that the function ofT. strigimanusstridulation is defensive, particularly against conspecific aggressors. This may reduce intraspecific competition for shells inTrizopagurus.
Underwater sounds of the haddock,Melanogrammus aeglefinus
Authors: Hawkins A. D. , Chapman C. J. 
Published: May 2009

It has not been known with certainty that the haddock produces underwater sounds of biological significance, though various authors have suggested the possibility.Descriptions are given of sounds (grunts and rasp-like noises) produced in particular behavioural contexts by haddock maintained in tanks, and of sounds recorded at sea and attributed to haddock. Oscillograms and a spectrogram of these sounds are given. It is suggested that the sounds are involved in aggression and self-defence.The sound-producing mechanism is described.
Mesopsammic Cnidaria from Plymouth (with systematic notes)
Authors: Salvini-Plawen Luitfried V. 
Published: May 2009

During a short stay at the Marine Biological Association Laboratory Plymouth (mid-September 1982) preliminary investigations of the interstitial fauna of marine sand were carried out. The sampling sites with the recorded Mollusca have already been communicated (Salvini-Plawen, 1984).As concerns mesopsammic Cnidaria, only a few findings have been made in British waters (Boaden, 1963, 1966; Harris, 1972). The present contribution reports not only new records for the Plymouth area and British waters in general, but also provides comparative knowledge of mesopsammic faunas.
Underwater observations on rocks off Stoke Point and Dartmouth
Authors: Forster G. R. 
Published: May 2009

SUMMARYA description is given of the commonest sublittoral algae and sessile animals found on rock at Stoke Point Reef and at the E. Blackstone rock near Dartmouth to a maximum depth of 28 m. The E. Blackstone fauna resembled that of Plymouth Sound. The marked change which has been found is ascribed to the greater turbidity of the water near Dartmouth and the increased shelter from wave action.
Observations in vivo on the breeding of Elminius modestus grown on glass slides
Authors: Crisp D. J. , Davies P. A. 
Published: May 2009

SUMMARYA more complete study of reproductive behaviour is possible where observations can be made on individuals. This is especially so in a population where each individual has a succession of breeding cycles which are not synchronous with those of other individuals. Continuous records of the breeding of individual barnacles is possible in species which have a membranous base. Individuals may be grown on glass slides and the reproductive condition determined by observations through the base.Reproduction in Elminius modestus takes the form of a succession of breeding cycles or broods, each cycle being initiated by copulation, oviposition and fertilization of the eggs in the mantle cavity. Here the eggs develop, and embryos are eventually liberated through the opercular valves.The time interval occupied by a brood varies both among individuals and with the season of the year. The time of development of the embryos appears to be a function of temperature alone, but the regeneration of the ovary depends upon the nutrition and food supply. When the ovary regenerates rapidly, as in the period of rising temperature, viz. in spring and early summer, another fertilization follows closely upon liberation, but in autumn and winter the ovary may not mature for some time after liberation, with the result that a large proportion of the population do not contain egg masses. In spring and summer the fecundity is probably limited by the rate of development of the embryos; in autumn and winter by nutrition.There is a slight tendency for eggs to remain in the mantle cavity for a longer period during the falling temperatures of autumn and winter than at corresponding rising temperatures in spring and summer.
On the Mode of Functioning of the Water Vascular System ofAsterias RubensL.
Authors: Binyon John 
Published: May 2009

SUMMARYExperiments reported in a previous paper have indicated a considerable water loss by isolated preparations of the tube feet ofAsterias rubenswhen ligatured in the protracted state. Because of its specialized structure, the podial diameter remains constant throughout the stepping cycle and this simplifies the procedure for measuring the surface area. Measurements of the internal hydrostatic pressure within the tube foot ampulla systems shows a maximum of about 30 cm water to be reached during the protraction phase of the stepping cycle, falling to nearly zero during the resting period. From these data it is possible to calculate a value for the permeability to water of the tube foot membrane, and such a value is compared with other membranes.By measurement of the total area of protracted tube foot membrane exposed by the animal when supporting itself in sea water, it is possible to arrive at a figure for the total water loss by the water vascular system. For a 50 g animal this amounts to some 0·5 ml./h. Experiments involving blocking or extirpating the madreporite, and with isolated arms, make it extremely improbable that this loss could be made good from this route.As alternative mechanisms, a slight hypertonicity due to the presence of excess potassium, or water movement as a direct consequence of the operation of an ion pump are discussed. In view of the hydrostatic pressure within the water vascular system the possibility of its functioning as a physiological kidney is also discussed. A possible alternative function for the madreporite is put forward.
A Note on the Elemental Composition of the Jaws of Goniada Maculata (Polychaeta: Goniadidae)
Authors: Gibbs P. E. , Bryan G. W. 
Published: May 2009

It has been concluded from studies of the elemental composition of the jaws of four Glycera species that a high concentration of copper is a structural feature of the glycerid jaw (Gibbs & Bryan, 1980). In Glycera gigantea Quatrefages, for example, the whole jaw when dried contains about 1–5% of copper, whilst zinc, calcium and magnesium, in roughly equal amounts, account for a further 1%. Copper is mainly confined to the distal half of the jaw and a concentration of 13% is present in the extreme tip; the other metals are more evenly distributed. Of non-metals, chlorine is concentrated in the distal tip along with the copper but sulphur is fairly evenly distributed and probably accounts for several percent of the dry weight.In view of these findings, it was decided to investigate the Family Goniadidae, a group of worms that are closely related to the Glyceridae (and often included in that family) but which are readily separated by the different structure of the jaw apparatus and also of the parapodia (see Hartman, 1950). In goniadids the jaw apparatus consists of a pair of larger toothed jaws (macrognaths) plus dorsal and ventral arcs of smaller, H- and Y-shaped jaws (micrognaths), the whole forming a circle around the tip of the proboscis. The present observations were made on Goniada maculata Oersted, the only goniadid species present in the Plymouth area, and a total of four specimens, all about 5 cm in length, from different areas (Salcombe, Rame Grounds and Cawsand Bay: see Marine Biological Association, 1957) were examined.
A Report on the Fauna of the Estuaries of the River Tamar and the River Lynher
Authors: Percival E. 
Published: May 2009

The following is an account of a faunistic investigation covering those parts of the Rivers Tamar and Lynher which are affected by the tide, and was carried out during a period of six months from June to November, 1928.Description of the Area.The Tamar forms a portion of the boundary between Devon and Cornwall and flows in a southerly direction along a more or less winding course. (Chart.) The extent of the stream dealt with is from Plymouth Sound to Weir Head, some 19 miles inland measured along the water course. For about 6 miles downstream from Weir Head, the valley is rather narrow with rock exposures at different places on the convex side of bends, the water being confined to a well-defined channel with steep sides, which are uncovered by the vertical contraction of the stream at low water. The remainder of the river, down to the sea has, generally, a mud bank on each side, except at occasional bends where rock is present, which is exposed at low water by the lateral contraction due to reduction in level. The upper 4 miles of this region has narrower mud-banks than has the lower portion. These mud-banks or -flats are for the greater part more or less plane surfaces, which may slope gradually into the bed of the main channel, as happens in the lower portion of the area, or they may slope suddenly downwards at the edge, thus forming a well-marked bank to the main channel. In many cases their landward edges lie below high-water neap tide, but in others they slope imperceptibly into the adjoining land surface.
Seasonality of the Association Between the Ascidian, Molgula Complanata, and the Commensal Copepod, Doropygus pulex
Authors: Schmidt Günter H. 
Published: May 2009

Commensal copepods were found abundantly in samples of the ascidian Molgula complanata Alder and Hancock taken from experimental panels for histological examinations (see Schmidt, 1982). As little data exists on the possible ecological importance of such association to the ascidian host (Gotto,1979 for review), the incidence of‘ infection’ was quantified in the present study over a period of 8 months.Between 31 October 1980 and 3 June 1981 specimens ofM. complanata( 6 mm maximum diameter) were removed from panels suspended from a raft in Langstone Harbour, Hampshire; 50–125 individuals per sample. Associated copepods found in the branchial basket were:Notodelphys agilis Thorell,Botryllophilus macropus Canu, andDoropygus pulex Thorell* (cf. fig. 2 in Schmidt, 1982). The former two species occurred sporadically, but the latter consistently. Owing to the relatively large, globular size ofD. pulex (caused by very inflated brood pouches), it almost filled the space provided by the branchial basket of smallM. complanta. Hence,D. pulex was found onlyone per ascidian, although 1–3 juveniles (several copepodid stages) were often present with the adult.On 31 October 1980,D. pulex was present in 64% of 115 animals examined. It is interesting to note that, despite such abundance,D. pulex has not been reported previously in association withM. complanata (Gotto, i960). On 28 November 1980, the incidence of ‘infection’ was still high (62 %) but thereafter declined (14 January 1981: 35 %; 10 February 1981: 34 %; 11 March 1981: 42 %) to a value of 13 % by 8 April 1981, around which it stayed until the end of sampling (3 June 1981).
Feeding And Absorption in Cerastoderma Eduee Under Environmental Conditions in the Bay of Marennesoleron (Western France)
Authors: Urrutia M.B. , Iglesias J.I.P. , Navarro E. , Prou J. 
Published: May 2009

Physiological processes involved in energy acquisition by the filter-feeding bivalve Cerastoderma edule (L.) (Mollusca: Bivalvia) were quantified under naturally fluctuating feeding conditions imposed by tidal cycles in the Bay of Marennes-Oleron. Physiological measurements were performed during two neap and two spring tidal cycles in order to cover a wide range of seston concentrations (TPM = 15–95 mg I-1). The main effect exerted by tides on the food supply was the resuspension of bottom sediments of low organic content, leading to a strong ‘dilution’ of suspended organic matter.Although filtration rate was found to increase with seston concentration, ingestion rate was strictly regulated by means of pseudofaeces production. Selection efficiencies for chlorophyll a (SEchl), overall organic matter (SE0), carbon (SEC) and nitrogen (SEN) were estimated and related to dietary descriptors. The following ranking was found for the efficiency with which different substrates were selected: SEchl>SEN>SEo>SEc. Absorption efficiency was found to depend on the organic content of ingested matter according to an exponential saturating function. Observed differences between carbon and nitrogen absorption efficiency were not statistically significant. Absorption rate was kept fairly constant through the wide range of seston concentrations and qualities.
Synchronization between moulting in Calocaris macandreae [Decapoda] and reproduction in its epibiont Tricella koreni [Polyzoa Ectoprocta]
Authors: Eggleston D. 
Published: May 2009

The ctenostomatous ectoproct Triticella koreni (G.O. Sars) occurs mainly on Calocaris macandreae (Bell) and Nephrops norvegicus (L.) but also on other Crustacea including Upogebia deltaura (Leach), Goneplax rhomboides (L.), etc. (Eggleston, 1969). Off Northumberland T. koreni occurs mainly on C. macandreae. C. macandreae moults from September to December (Buchanan, 1963).In order to investigate how the ectoproct copes with this annual substrate loss collections of C. macandreae made in all months were examined. Some of the material was provided by Dr J. B. Buchanan; all came from mud bottoms 40 fathoms deep east of Blyth and was collected between 1961 and 1963. Ten random C. macandreae were taken from each month's collection. One periopod on each Calocaris was selected by the use of random numbers. The number of T. koreni zooids, the number of developing zooids, the number of oviparous zooids and the number of free eggs in each oviparous zooid on each selected limb were counted.The data recorded from the ten limbs from each collection examined are shown in Table 1.T. koreni zooids are hermaphrodite. The gonads and free spermatozoa and eggs can be seen through the translucent body wall. Spermatozoa and eggs rarely occur in quantity in the same zooid. Some zooids are so packed with sperm as to appear opaque; up to thirty-one eggs were seen in other zooids. The egg is small and unpigmented; the larva is unknown.From November to June T. koreni colonies grow rapidly and have a high proportion of developing zooids. From July to October growth slows and reproductive activity increases.
Rate of Spiculogenesis in Clathrina Cerebrum (Porifera: Calcispongiae) Using Tetracycline Marking
Authors: Bavestrello Giorgio , Cattaneo-Vietti Riccardo , Cerrano Carlo , Sara Michele 
Published: May 2009

The use of tetracycline marking has enabled the daily production rate of calcareous spicules in the Mediterranean calcisponge Clathrina cerebrum to be measured. Twenty-four hours after starting the experiment newly formed spicules represent about 10% of the total spicule number. No differences in this rate of spicule secretion were detected between the samples tested under light and dark conditions. The growth rate of the tetracycline-tagged spicules in Clathrina cerebrum is similar to that found for other calcispongiae using other methods.Spicules constitute the skeleton of sponges and are the most important taxonomic character in this group. In calcareous sponges many details of the process of spicule secretion are well known (see Simpson, 1984 for review), particularly their chemical composition and crystallographic structures (Jones, 1955, 1967; Jones & Jenkins, 1970; Ledger, 1976). Ultrastructural studies were carried out on the cellular processes involved in spiculogenesis (Jones, 1970; Ledger & Jones, 1977), but little is known of the rate of spicule secretion. This phenomenon has been studied here by tetracycline marking of newly calcified spicules, triactines. Tetracycline forms complexes with calcium or other metal ions which are easily incorporated into biominerals; consequently it can be used to label the growth of biocalcified structures (Ibsen & Urist, 1962). This method is commonly used in medical research (Urist & Ibsen, 1963; Sandhu & Tonna, 1986; Milch et al., 1957; Van Linthoudt et al., 1991), and has also been employed in studies on biocalcification in marine organisms, such as echinoderms (Gage, 1992) and molluscs (Nakahara, 1961).