The ctenostome bryozoan Alcyonidium diaphanum is widespread and abundant in the coastal waters of England and Wales. It was recorded in 77–90% of beam trawl catches in the eastern English Channel and southern North Sea, and in 53–73% of catches in the Bristol Channel and Irish Sea. The maximum catch rates in these two study areas were 1410 and 751 kg h−1 respectively. Alcyonidium diaphanum was most abundant in the greater Thames Estuary. Additional data from the North Sea indicated that A. diaphanum is widely distributed throughout the southern North Sea. Alcyonidium diaphanum was found intertidally in only seven of 99 locations sampled. Several different morphotypes were observed, ranging from cylindrical to lobate forms. The distribution patterns of various morphotypes are discussed.

Six new marine species of the silica-scaled heterotrophic genus Thaumatomastix are formally described: two were found in Canadian Atlantic Ocean coastal waters (T. asymmetrica sp. nov. and T. sablensis sp. nov.) and four from Canadian Pacific Ocean coastal waters (T. inornata sp. nov., T. multipora sp. nov., T. gwaii sp. nov. and T. curvata sp. nov.). These discoveries more than double the number of known marine species of this genus from four to ten. The scale structures of all differ significantly from those of previously known species and therefore warrant erection as new species. Amended descriptions of two previously little-known freshwater species (T. triangulata and T. nigeriensis) are provided based on specimens found in freshwater ponds and lakes in Ontario, Lanada, and provide evidence refuting the recent published proposals to transfer T. triangulata back to the photo-autotrophic genus Chrysosphaerella and to transfer T. nigeriensis to the related thaumatomonad genus Reckertia. Until now, all known species of Reckertia (including several taxa previously classified in Thaumatomastix) were marine. This paper describes the first known freshwater species of Reckertia (R. hindoni sp. nov.) found in two separate Ontario ponds. The similarities and differences among many of the marine and freshwater species of Thaumatomastix suggest a common ancestor but significant evolutionary divergence over time and space.

It has previously been shown (Ford, 1, p. 284) that herrings with fully ripened roes or milts form a considerable proportion of the landings by commercial drifters at Plymouth during December and January. Although naturally-deposited spawn has rarely been obtained from the sea-bottom in the district, the fact that newly-hatched larvæ occur in abundance provides evidence that actual spawning occurs locally. It has also been shown that from the end of September onwards, ripe fishes may be taken in stop-nets in Plymouth Sound, and even in sprat-seines in the estuarine waters of the River Tamar. A number of interesting and important questions is suggested by these observations. For example, do the ripe herrings which frequent the River Tamar actually spawn there, and if so, are they morphologically identical with those which spawn at sea, or are they of a different character? Would eggs deposited in the river be successfully fertilised and able to endure the periodic freshening of the water? Are the morphological characters of the offspring in any way dependent upon the environmental conditions under which they are developed?

Seasonal changes in spatial structure of biomass of submerged aquatic vegetation (SAV) and environmental variables were evaluated in Celestun Lagoon, an estuarine habitat in Mexico. Geostatistical techniques were used to evaluate spatial autocorrelation and to predict the spatial distribution by kriging. The relative contribution of 11 environmental variables in explaining the spatial structure of biomass of SAV was evaluated by canonical correspondence analysis. Spatial partitioning between species of SAV was evident: the seagrasses Halodule wrightii and Ruppia maritima dominated the seaward and central zones of the lagoon, respectively, whereas the green alga Chara fibrosa was constrained to the inner zone. The spatial structure and seasonal variability of SAV biomass were best explained by organic carbon in the sediments, salinity and total suspended solids in the water column. Analysis at different spatial scales allowed identifying the importance of spatial structure in biotic and abiotic variables of this estuarine habitat.

In some metazoans, the body surface is entirely or partly covered with an array of nipples about 100 nm or less in height. This structure, a nipple array, is sometimes called the moth-eye structure because it serves as an anti-reflection property on the compound eyes of a night moth. The nipple array is supposed to be a multifunctional structure since this structure occurs in various species across different taxa. Here, we hypothesize that the nipple array may prevent the settlement of epibionts that are often a nuisance and potentially cause serious problems for the host. Using a synthetic film that imitates the nipple array, we tested the substrate selection within ascidian larval settlement. The results indicate that the nipple array has anti-fouling properties, since more larvae settled on the flat surface than the nipple array (P < 0.01, paired t-test). The present results demonstrated that the nipple array potentially serves an anti-fouling function on the body surface, which should be important especially for sessile organisms.

Current flow regime, bathymetry and substratum angle were found to influence the density and distribution of the following anthozoan species at Lough Hyne Marine Nature Reserve, Ireland: Corynactis viridis, Alcyonium digitatum, Caryophyllia smithii, Anemonia viridis and Anthopleura ballii. Density variation was found on inclined, vertical and overhanging cliff surfaces for species found on hard substratum (Corynactis viridis, Alcyonium digitatum and Caryophyllia smithii). All species showed significant variation with increasing depth and between sites with different water flow rates.

Dynamics of Synechococcus (Syn), Prochlorococcus (Pro) and picoeukaryotes (Euk) was studied at 92 stations in the Pearl River Estuary and adjacent shelf waters in the winter of 2006 using flow cytometry. The average cell abundance of photosynthetic picoplankon (Pico) was 104 cells/ml. Picoeukaryotes was the dominant group in the inner estuary where Pro was absent. Synechococcus was dominant in the coastal and open waters. The proportion of Pro was higher in the open than in the coastal waters. The change of Pico community structure from the inner estuary to the open waters is related to the changes in hydrochemical dynamics. The vertical variations in the abundance and community composition of Pico were not significant. The abundances of Pro and Syn were positively correlated with temperature, salinity and pH, whereas they were negatively correlated with dissolved oxygen (DO), suspended sediment concentrations (SSC) and nutrients (nitrogen, phosphorus and silicon) concentrations. But the correlations between %Euk (as of total pico) and these environmental factors were opposite to those between the abundance of prokaryotic cells (Pro and Syn) and the environmental factors. %Euk had significant negative correlations with temperature, salinity and pH, and positive correlations with DO, SSC and nutrients. There were differences in the niches between prokaryotic cells and picoeukaryotes. Prochlorococcus and Syn were dominant in the warm waters with high salinity, low SSC and low nutrient concentrations, while %Euk was higher in the cold waters with low salinity, high SSC and high nutrient concentrations. Results of principal component analysis and regression analysis indicated that the relationship between the abundances of Pico and the environmental factors was a compound function (y = b0(b1)x), and that between the abundances of Pro, Syn or %Euk and the environmental factors was a linear function.

A description has been given of a mating which produced a great range of eye-irregularity in the offspring. Not only were the size, shape, and pigmentation affected, but the eye-structure itself, many cases occurring in which one eye or even both eyes were missing at birth.

This experiment adds another proof to the statement that the farther removed from the normal an animal is, the lower its viability. The mortality was much higher amongst the abnormals, and breeding experiments with the survivors were exceedingly difficult on account of the trouble experienced not only in rearing them to maturity, but in finding suitable mates. The cannibalism of the males of this stock made it almost impossible to use them, and small, not too vigorous, males had to be sought in the Albino No-white strain.

In three of the One-eyes, i.e. those in which one eye was present at birth, and no trace of a second could be seen (even with a high power), a very imperfect second eye developed later, after several moults had taken place. An example, CN.220c, is illustrated in Text-fig. 5 (List, p. 384).

The formation of ‘teeth’ in immature Nucella lapillus (L.) is indicative of a stoppage in growth. Along the western coasts of southern Britain the proportion of individuals showing these growth disturbances is predictably related to the exposure of the shore to wave action. Farther east the proportion is much higher but not obviously so related. Sharp discontinuities separate eastern and western populations. Possible reasons for the differences are discussed and it is concluded that great care must be exercised when applying information about this species derived from the one coast to situations on the other. The potential value of this species as an indicator of environmental change is considered.

As aids to the phyletic interpretation of the newly described Chrysochromulina pachycylindra Manton et al., some hitherto unrecorded gatherings of C. microcylindra Leadbeater and C. cyathophora Thomsen, from South Africa and South Alaska respectively, are introduced, thereby amplifying the type descriptions of both species, which were previously known only from Europe. Characters shared between C. pachycylindra and C. microcylindra are numerous, including a capacity for transverse fracture of their cylinders not previously noted in the latter. This suggests an exceptional degree of affinity between these two species in spite of gross differences in relative dimensions of different parts of their respective cylinder scales. On the other hand the general resemblance between C. microcylindra and C. megacylindra (Leadbeater, 1972), previously noted, is unaffected by these findings and it is concluded that all three species could be treated as a closely related subgroup within the genus Chrysochromulina. In contrast, C. cyathophora is shown to be so different as to be interpretable only in terms of parallel evolution from a separate prototype source, the plate-scales in particular being so far unique in the genus in being thin, rimless, peculiarly patterned and convex when seen in section. The mere presence of cylinder-scales is thus seen to be insufficient evidence of phyletic affinity unless confirmed by other characters, among which the details of the plate-scales are probably the most important.

Many techniques have been devised to overcome certain problems encountered when narcotising actiniarians. From these a few have been selected as being at least partly successful. Further modifications to these narcotising methods have been introduced in order to block more effectively the nervous pathways responsible for secondary contraction reactions. Until now, perfectly expanded specimens have been achieved largely by chance. This paper records experimental results and arising problems as a contribution to a better understanding of the process and a more consistent rate of success.

Epibenthic macroalgae were observed to grow more abundantly on the upper surface of the Japanese scallops Patinopecten yessoensis (Bivalvia: Pectinidae) than on other available substrate. A field experiment to examine the hypothesis that colonization of live scallops protects macrophytes from grazing by sea urchins Strongylocentrotus nudus and S. intermedius was performed. Algal growth in the areas with urchins was compared with that in the enclosures without urchins. Each enclosure contained two live scallops, two empty shells, and one rock similar to scallops in size and shape. Twenty live scallops, 16 empty shells and ten rocks were marked and left outside the enclosures. After three months there was no difference in macrophyte mean percentage cover on live scallops inside and outside the enclosures. Percentage cover of macrophytes on dead scallop shells and rocks was significantly lower outside the protective enclosures as compared to unprotected areas. The results support the hypothesis that scallops serve as mobile refugia for macroalgae from urchin grazing.

Portuguese sole, Synaptura lusitanica, were collected from the Portuguese coast, between April 2001 and March 2002, to examine feeding habits, age and growth, and sexual cycle. Synaptura lusitanica fed on few prey items, its diet mainly composed of polychaeta, bivalvia and cephalochordata. Significant differences were found between the proportion of prey items according to season, length class of fish and coastal area. The main differences related to fish size were the higher ingestion of bivalvia by larger fish, in the west coast area, and the increase in the important cephalochordata for fish larger than 300 mm total length, in the south coastal areas. Polychaeta presented a lower importance in the spring–summer period while bivalvia increased its values in the autumn–winter period. Cephalochordata were more important in the autumn–winter period, but only for fish larger than 300 mm total length and in the south coastal areas. Vacuity was extremely high (mean value of 52%). Ages of S. lusitanica were determined from sagittae otoliths. The length of fish analysed varied from 157 mm to 480 mm, and the oldest fish was age 8. The von Bertalanffy growth equation parameters differed little between sexes, being the asymptotic length obtained for females higher compared to males. The highest values of the gonadosomatic index were obtained in summer, which was the period when the highest percentage of individuals in the spawning stage were recorded. Therefore, the spawning season seems to be from mid-spring (May) until the end of summer (September).

The Phylum Chaetognatha consists of morphologically and biologically similar species and its relationship with other invertebrate groups is obscure (Hyman, 1959; Ghirardelli, 1968). The possibility of regenerative power has been investigated as one of the clues to the affinity of the phylum. Kulmatycki (1918) made cross-sectional and diagonal cuts through the body and tail fin of Spadella cephaloptera Busch and reported that this species could regenerate the whole caudal section including the body proper. Further support for regenerative ability came from Pierce (1951) who caught 26 specimens of Sagitta enflata Grassi and Sagitta helenae Ritter Zahony which appeared to be in the process of regenerating their heads (presumably lost to a large predator). He noted that the loss of this section of the body did not kill the animal. Both Kulmatycki and Pierce are cited in Hyman's (1959) important review of the phylum and headless chaetognaths have been referred to as animals with regenerating heads (e.g. Almeida Prado, 1968).

The cirri of the digital tentacles of Nautilus pompilius are covered by annular ridges, more pronounced on the oral (adhesive) than the aboral side. On the oral side the epithelium is thicker on the proximal and outer surfaces of the ridges than on their distal surfaces. Prominent electron-dense granules occur in the cells of the thick epithelium, but are absent from the thin epithelium and the epithelium of the aboral surface. These granules contain mucopolysaccharide and may be responsible for adhesion.

The digital tentacles of Nautilus are used for attachment to, for example, prey, the substratum, or the partner's shell during mating. Their general structure and histology have been described by Owen (1832), Willey (1898), Barber & Wright (1969), Fukuda (1987) and Kier (1987). The mechanism of adhesion is still uncertain. Barber & Wright (1969) report epithelial cells of two types: pigmented cells containing pigment granules 0–5–1 µm in diameter, interspersed with a small number of mucus-producing cells which may help with the adhesive process.

Since April, 1921, observations of temperature and salinity have been made at depths from top to bottom of the sea at Station El, 20 miles to the south-west of Plymouth, where the depth is 70 metres. These observations already throw some light on the causes of different sea temperatures during the same month in different years. As these temperature differences from year to year play an all-important part in the life of cold-blooded marine animals (1), it is of particular interest not only to follow their seasonal changes, but to arrive as far as possible at the causes which govern them.

Changes in salinity and the temperature conditions during 1921 showed a marked inflow of warm highly saline Atlantic water into the English Channel, and a very marked inflow into the El area during September, October and November of that year (2). From that time until the end of 1923 there has been an irregular fall in salinity of the water at El.

DNA barcoding based on the cytochrome c oxidase subunit I (COI) gene in mitochondrial DNA has been adopted as a global biological identification system for animals due to its accuracy compared with other classical taxonomic methods. The objective of this study was to establish a reference library with generated barcodes. A total of 84 fish specimens belonging to 37 commercially important marine fish species, representing five orders, 14 families and 30 genera, were sampled along the Tunisian coast and barcoded for the first time, obtaining 637 bp sequences. The average Kimura 2-parameter (K2P) distances within species, genera and families were 0.52, 6.86 and 14.60%, respectively. The Maximum likelihood (ML) tree revealed distinct clusters in concurrence with the taxonomic status of the species. Our results confirmed the authentication of the barcode approach for the identification of the species examined and provide valuable information that would help ichthyologists to achieve better monitoring, conservation and management of fisheries in Tunisia.

In a field experiment, the accumulation of trematode (Echinostomatidae) metacercariae by the New Zealand cockle Austrovenus stutchburyi was compared among treatments with different seabed hydrodynamics and sedimentation rates. There was no significant difference among the treatments in the rate at which cockles accumulated metacercariae, suggesting that infection rates are not influenced by water flow conditions within the normal range experienced in natural habitats. There was, however, substantial spatial variation in infection rates among the experimental plots. This result indicates that metacercarial accumulation varies horizontally as well as vertically within the intertidal zone.

A hitherto unreported association between the isaeid amphipod Photis longicaudata and the hexacorallian Cerianthus lloydii is described and illustrated from material collected near Millport, Clyde Sea area. By building their tubes around the outside rim of the anemones' tubes, this amphipod presumably gains proximity protection from predators.

The six drawings reproduced in Plates III and IV were made at sundry times from stages that I succeeded in obtaining in the years 1889 and 1890. The three stages of the common sole were procured after my quarto book on that fish was completed, and they enable me to supplement the account of the life-history of the species given there.