four captive specimens of sandbar shark carcharhinus plumbeus from the l'oceanogràfic aquarium (valencia, spain) were studied: one adult female (192 cm total length [tl]) reared for five months, her two new born pups (a female, 61 cm tl and a male, 60 cm tl), and one juvenile female, born in captivity, dead at nine months of age (90 cm tl). comparative measurements of length and diameter of vertebrae from three different regions of the vertebral column showed that vertebrae above the pelvic fins (nos. 59–63) are the biggest in this species. consequently, these vertebrae are preferred for age estimation given that growth marks are easier to identify. the only present mark in the vertebrae of the two neonate specimens was at the edge and was interpreted as the birth mark. a mark at a similar distance was present in the vertebrae of the juvenile and adult females.

adult female vertebrae analysis shows 23 marks without any variation in the banding pattern distribution during free-range growth and short period of captivity. the juvenile individual shows two clear growth marks developed after birth. the presence of these marks in a 9-month old individual suggests that the counting of all vertebral growth marks as annuli may result in the overestimation of age for this shark species.

Gonad of the Mediterranean pectinid Flexopecten glaber was studied in order to describe the morphology and the ultrastructural characteristics of the mature spermatozoa. The spermatozoon has a 2.5 μm pyriform head and a 40–45 μm flagellum. The four mitochondria of the mid-piece are 0.6 μm in diameter. The nucleus contains dense chromatin fibres and possesses two depressions: a wide (0.19 μm) and deep (0.58 μm) sub-acrosomal one, and the other at the base of the head, less deep (0.36 μm) and less wide (0.12 μm). The objective was to situate this scallop in the phylogenetic diagrams found in the literature concerning the commercial pectinid species.

Studies of sea turtle epibiosis have focused on the diversity and ecology of facultative commensalisms and less attention has been given to parasitic associations, in which the epibiont species derives nutrients from the tissue of the host turtle. We present the first description and quantitative survey of the parasitic isopods Excorallana costata, Excorallana bicornis and Excorallana oculata on loggerhead (N = 79) and hawksbill turtles (N = 23), and E. costata on olive ridley turtles (N = 9), nesting on Praia do Forte, Bahia, Brazil during the 2009–2010 season. Excorallana costata was the most common isopod species (N = 651), followed by E. bicornis (N = 77) and E. oculata (N = 20). Patterns include: (1) E. costata exhibited a higher frequency and intensity of parasitism than E. bicornis and E. oculata and (2) loggerheads hosted parasitic isopods at a higher frequency and intensity than hawksbills and olive ridleys. We also detected temporal shifts in the occurrence and intensity of parasitism across the nesting season, which strongly suggests that turtles were parasitized by all three isopod species during their internesting periods. Because parasitic isopods were observed only rarely prior to the 2009–2010 turtle-nesting season and have continued to be common in subsequent seasons, it is important to gain a better understanding of the basic biology of these interactions, the reasons for their recent emergence, and the potential biological impacts on turtle, as well as isopod, populations.

A number of mangrove systems with associated tidal flats occur in Coiba Island, located off the Pacific coast of Panama, two of which were selected for the present study: Santa Cruz and El Gambute. Three transects were selected on each tidal flat and three sampling sites were arranged along each one: lower, middle and upper intertidal. During 1997, two samplings were carried out at each site, in February and November. The results of the faunistic studies revealed the presence of ten species of Orbiniidae, two of which belonged to the genus Leodamas. Leodamas minutus sp. nov. is easily distinguished from all other species within the genus by having a cylindrical thorax composed of 13 chaetigers, the first three chaetigers without notopodial lobes, thoracic neuropodia without postchaetal process, and abdominal neuropodia, short, bilobed and with protruding acicula. Leodamas platythoracicus sp. nov. can be recognized by its thorax, distinctly flattened in the posterior half and consisting of about 19 chaetigers, by its thoracic neuropodia, with many spines arranged in one or two rows and few, if any, slender capillaries, and by the shape of its abdominal neuropodia, which are long and subterminally notched and bear a distal process.

Three species: Oxyonchus orientalis sp. nov., O. sakchalinensis sp. nov., and O. nicholasi sp. nov. (Thoracostomopsidae: Nematoda) are described and illustrated with the aid of light microscopy and laser-scanning microscopy pictures from sediments of Far Eastern Seas (the one former species from the Sea of Japan, Eastern Russia and the two latter species from the Sea of Okhotsk, Sakhalin Island). Generic diagnosis is emended for identification of Oxyonchus. Oxyonchus orientalis sp. nov. has short cephalic sensillae (0.6 cephalic diameters), strongly developed broad mandibular plate with irregular arrangement of numerous small denticles. Oxyonchus sakhalinensis sp. nov. is particularly characterized by the weakly short cephalic capsule, and the rounded thin mandibular plates with 10 denticles. Oxyonchus nicholasi sp. nov. can be differentiated by the structure of the cephalic armament (well developed capsule, fenestrae and incisions), numerous long cervical setae and tail shape. The distribution patterns of the various Oxyonchus species was suggested.

This work is an interpretation of a chronological data set on abundances of estuarine soft substrate invertebrates using an ecological approach. The data were collected in the framework of the European programme COST 647 (Coopération Scientifique et Technique) on coastal benthic ecology which terminated in 1992. Species numbers and selected environmental factors were recorded at two stations in the Baie de Somme (France) from 1981 to 1992. Inter-annual and seasonal variations in benthos numbers were analysed using a plotting procedure based on a non-probabilistic approach, proposed by Andrews in 1972. Ecological groups of species were identified and succession in time described, coinciding with alterations in the landings of cockles Cerastoderma edule. The chronological data set was processed through the application of the cumulated function, giving directly intensity and duration of any changes in relation to the climate and water quality, especially potential eutrophication manifestations.

A fixed bottom net was used to study the relationship between the horizontal and vertical density distribution of polychaete and cirripede larvae over an inshore rock platform.

Strong horizontal density distributions were obtained close to the bottom in many species from both groups, while the vertical samples showed larvae to be distributed towards the bottom both during the day and at night. It is suggested that the concentration of larvae within the slow-moving bottom water was responsible for the observed limited lateral larval dispersal.

The results are discussed in relation to their bearing upon a number of problems within the field of meroplanktonic ecology.

The rock goby, Gobius paganellus one of the most common gobiid fish in Bizerta lagoon (north-east of Tunisia), is a gonochoric species that belongs to the Gobiidae family. This study provides the first detailed information of its reproductive biology in lagoon environments. Gobius paganellus was sampled monthly from January 2005 to December 2006 involving 1486 specimens. Total length distribution ranged between 38 and 125 mm. The maximum recorded total lengths were, respectively, 122 mm and 125 mm for female and male. Over the entire population, the sex-ratio was unbalanced in favour of females. According to months, a predominance of females sex-ratio was recorded during the spawning period while according to body size, males were dominating among larger size-classes. In both sexes, the variation of the gonadosomatic index (GSI) was independent of size. Macroscopic and microscopic examination of the gonads added to the monthly monitoring of gonadosomatic index and hepatosomatic index showed that gonads development begins in October and spawning period extends from December to March. The cyclic pattern of gonads development was determined by histology. Results indicated that G. paganellus exhibits a group-synchronous oocyte development. The sizes of first sexual maturity related to 50% of mature individuals were 78.3 mm (CI95: 77–84 mm) for males and 79 mm (CI95: 75–85 mms) for females. The discussion part underlined the impacts of some environmental factors and antropization of this lagoon on sexual cycle of G. paganellus.

This paper contains anatomical descriptions of some British species whose systematic position has hitherto been uncertain because of the absence of detailed knowledge of their structure. To these descriptions are added notes on anatomical points of interest connected with other species.

Some of the facts gained have a general systematic bearing which will be pointed out as they occur in connection with the descriptions, or in the discussion at the end of the paper. I am indebted to Dr. Allen, Mr. W. Edgar Evans, Mr. E. Elmhirst, Miss M. Delap, and Dr. T. A. Stephenson for material, and to Dr. Esdaile for valuable guidance.

I am indebted to the courtesy of Dr. Allen for the opportunity of examining the collections of these two orders of Crustacea in the Huxley's material.

None of the species are new to science, and but few of them present any features worthy of remark. The chief interest of the collection lies in its bearing on the known geographical distribution of the species captured for, out of a total of twenty-eight, no fewer than sixteen are recorded for the first time from localities south of the British Islands, while only eight of the species have previously been recorded from the Bay of Biscay. The bathymetrical range of five of the species recorded has been considerably increased by this material.

The population structure, size at maturity, reproductive period, recruitment and habitat use were studied in a population of the grapsoid crab Cyrtograpsus altimanus in an intertidal mussel bed at San Antonio Bay, Argentina. Samples were taken from October 2000 to January 2002. Crabs were sized and sexed to estimate size–frequency distributions (SFD). Modal groups of males and females were the same. Growth, evidenced by the shift to right of SFD modal classes, was observed in spring, summer and autumn. Size at maturity of females varied seasonally. Ovigerous females were found in winter, spring and summer, but two discrete recruitment events (in spring and autumn) are proposed. Based on the maximum male and female sizes found in the mussel bed, a size constraint is proposed that forces large crabs to migrate to cobblestone adjacent habitats.

The morphology of the zoeal stages IX and XI of the shrimp Thalassocaris lucida is described and illustrated in detail from plankton specimens identified by barcoding of the mitochondrial 16S ribosomal RNA gene (sequence similarities 99.4–99.6%). The present study confirms the larval morphology of Thalassocaris, that shows distinct features within Pandaloidea: (1) carapace broad and dorsoventrally flattened, (2) coxal endite of maxilla with only one lobe, (3) basis of third maxilliped with a distal globose lobe. On the other hand, the funnel-shaped eyes, and the development with long series of larval stages of Thalassocaris indicate affinities with some genera of Pandalidae which corroborates the results of recent phylogenetic analyses in abandoning the family status of Thalassocarididae.

Dispersion in a littoral population of Pagurus bernhardus in south-west England is shown to be random, with members demonstrating no evidence of site attachment. Movement patterns within the population are shown to be asynchronous and random, and to be dictated by the quantity and quality of each individual's shell contacts. These, in turn, affect the time that individuals spend within the habitat. This implies that population dynamics and residence times are so influenced by the availability of suitable empty gastropod shells that movement and migration in hermit crabs should be regarded as resource-dependent phenomena.

The following is a report on the Cœlenterate plankton taken off the Northumbrian Coast in 1924 during cruises of the Evadne of the Dove Marine Laboratory, Cullercoats, Northumberland. The work has been carried out under the supervision of Professor A. D. Peacock to whom I am indebted for much helpful advice. I must thank Professor A. Meek of Armstrong College, Newcastle-upon-Tyne, for so kindly providing the material, and Miss M. Yeats for the use of her notes on the 1924 surface medusae. Mr. P. L. Kramp of Copenhagen was so good as to check my identifications of certain specimens hitherto unnoted from Northumberland, and for this service I express my obligation. Dr. Allen, Director of the Plymouth Marine Biological Laboratory, and Capt. Totton of the British Museum, have also been kind enough to assist in questions of nomenclature. My own work consisted of the investigation of middle and bottom water samples and Miss Yeats' results on surface samples have also been incorporated here to make the yearly report complete.

Although the Isle of Wight has been a favourite haunt of the geologist and the palæontologist, references to its present marine fauna are exceedingly rare in zoological literature. Early in May of the present year, however, I had an opportunity, at the suggestion and through the kind hospitality of my friend Mr. Poulton, of examining the littoral fauna of the eastern shores of the island, and of making a considerable collection of zoological specimens. A list of the species which I obtained will be published as soon as I have had time to complete the examination of them; but several of the Ascidians throw so much light upon the brief and obscure descriptions of certain species, that I believe it will be serviceable to give a full account of them without further delay, especially since the pressure of other work may prevent an early appearance of the complete list.

The present contribution deals with the measurements of fifty-two samples of Biddulphia sinensis collected by Hensen net hauls from the Ministry of Agriculture and Fisheries research ships George Bligh and Onaway, working in the southern North Sea between 1932 and 1938. With one exception in which there were only seventy available, the samples consisted of a hundred cells and the unit of measurement was that employed in Part I of this paper (Wimpenny, 1936). The dimension used was the greatest width (apical axis), and care was taken to see that the cells measured were lying flat, to give the true maximum of their elliptical cross-section. For convenience in tabulation and to avoid random fluctuations due to too small grouping of the data, the measurement units have been taken in pairs in the presentation of all the sea results, each arbitrary unit being equivalent to about 8 μ. The measurements from cultures, where the samples were sometimes fewer than a hundred, have been 4μ units.

At a time like the present, when the Empire we have inherited stands facing a crisis of its fate, when indeed the whole structure of civilization as we know it has seemed to sway, when that which generations of earnest thinkers have dreamt of as the progress of the race recoils before the forces it has itself unchained, it is difficult to restrain a feeling of incongruity in discussing any subject that has no obvious bearing on the greater problems of the hour. But I am convinced that we are following the right course in carrying on, with such help as remains available, the work of this Association, whose object is the advancement of Science, Literature and Art. In the short, swift cataracts of war, no less than in the gentler, steadier flow of peace, these matters of the mind have still their power.

Recently Jones & Wills (1956) have related the attenuation of light in the sea and in estuarine waters to the concentration of suspended solid matter. The attenuation was measured with an in situ hydrophotometer with a beam acceptance angle of approximately 3.20°. The concentration of suspended materials was determined by filtering in the case of natural samples or by adding known weights of kaolin or mud to tap water. In the discussion of their data and methods they have made application of the difFraction theory for opaque particles relatively large compared to the wave-length of light.

The pinnate (feather-shaped) hydrocauli (stems) of Aglaophenia harpago are dish-shaped with the food catching hydranths borne on the convex side of the lateral branches, a morphology recognised as an adaptation to feeding from unidirectional currents. A. harpago experience unidirectional currents because the hydrocauli are able to rotate close to their bases on an articulation in the perisarc (the tubular exoskeleton) so that the concave surface always faces into the current and the hydranths face leeward. The structure of this articulation, revealed by light and electron microscopy, is described and its mechanism interpreted. The articulation consists of two oblique grooves of thin flexible perisarc which traverse around the hydrocaulus at an angle of 62–65°. The grooves terminate in areas of perisarc divided into longitudinal lamellae (probably of structural protein). The grooves and lamellae confer the flexibility which allows the hydrocaulus to ‘fold’ up to 90° clockwise or anticlockwise across each groove. The lamellae maintain the longitudinal support necessary to prevent the hydrocaulus collapsing.

1. Measurements of Carcinus, comparable to those taken by Weldon at Plymouth 40 years ago, have been made on material from three Irish localities, the observations in each area extending over three years. The three localities afford different environments, one having no silt, one a moderate amount and the other much silt.

2. The results support the view that the change in the ratio frontal width/ carapace length with increase in body size is due to differential growth in the individual and is not caused, as Weldon supposed, by the continuous removal through natural selection of those crabs with a relatively wide frontal aperture. Measurement on the growth of individuals confirms this view.

3. A striking fact which emerged from Weldon's work was that the ratio mentioned above showed a successive diminution in each of the three years covered by the observations. A precisely similar diminution has been found at each of the Irish localities, and it is shown that the annual differences are mathematically significant.

4. The results disprove Weldon's hypothesis that the change in the ratio is correlated with the slow accumulation of silt in Plymouth Sound. The Irish locality with most silt has the widest frontal aperture and the intermediate locality the narrowest. It is also shown that the yearly trend towards a lower value for the ratio cannot be continuous, for the rate of change is too rapid to be maintained indefinitely, and the values obtained in the Irish localities overlap those at Plymouth 40 years earlier. Possible explanations of the changes are discussed.

5. The differences between populations from the three localities in any year are much less marked than the annual differences at one locality, and are not generally significant. Though small, however, they do show a consistent sequence among the three localities (but not corresponding to the order for siltiness).