The genus Callinectes comprises seven species of blue crab found on the Brazilian coast, almost all are recorded in Cachoeira River estuary. The objective of this study is to analyse distribution of Callinectes species in the estuary of Cachoeira River (Ilhéus, Bahia). Monthly collections were conducted in the low tide of neap tide for a year and in five stations distributed according to the estuary salinity gradient. Six traps were assembled and submerged at each station for two hours. Sediment samples were collected for granulometric characterization and measuring of organic matter content. Temperature, salinity and pH were also measured in the bottom water, as well as water transparency at the start of each collection. Five species were collected: Callinectes danae, C. ornatus, C. exasperatus, C. larvatus and C. bocourti. The species presented different distribution patterns based on the salinity gradient and transversal profile of the estuary. Only C. danae was found in all collection points, and was the most abundant species throughout the study period. Callinectes ornatus was restricted to external estuarine areas, which presented higher salinity and transparency values. Callinectes larvatus predominantly occurred in the external station and estuary partitions, mainly in the margin. In spite of the occurrence of C. exasperatus throughout the entire estuary, this species was restricted to the margin. This study supports the assumption that species distribution patterns of this genus are the result of both variable influence, namely salinity, and complex intraspecific and interspecific relations between the congeneric species.

A detailed analysis of beak length to body length and weight measurements was carried out for the onychoteuthid squid Moroteuthis ingens, in the Falkland Islands region of the South Atlantic. Lower and upper rostral lengths were both good predictors of mantle length and body weight. In addition, the relationships of freshly dissected beaks to mantle length and body weight were significantly different to those of beaks dried before measuring, with dried beaks being better predictors of both variables.

A considerable amount of information on Southern Ocean squid biology has been obtained from analysis of beaks in the stomach contents of predators (Clarke, 1980,1983). Beak analysis can be particularly useful as it provides information on the species preyed upon as well as estimates of squid size and biomass ingested (Clarke, 1983, 1986).

Resource partitioning is considered one of the main processes driving diversification in ecological communities because it allows coexistence among closely related and ecologically equivalent species. We combined three complementary approaches, i.e. the evaluation of foraging behaviour, diet composition and nutritional condition (RNA:DNA ratio), to assess feeding by two closely related (sister) butterflyfishes that are syntopic in Puerto Rico. Chaetodon capistratus had a higher abundance and higher bite rate and selected octocorals and hard corals for feeding, whereas Chaetodon striatus fed preferentially on sandy substrates. Cnidarians and polychaetes were the most representative diet items for both species, but C. capistratus preferred the former (Feeding Index of 74.3%) and C. striatus the latter (Feeding Index of 60.4%). Similar RNA:DNA ratios for both species suggest that, although they differ in feeding rates and diet, C. capistratus and C. striatus have similar nutritional fitness. Therefore, these species are both zoobenthivores but show clear differences in their substrate selection. The differences in the use of foraging substrate by C. capistratus and C. striatus, despite their close phylogenetic relationship and similar diets, suggest that these species coexist by resource partitioning.

The olfactory epithelium of developmental stages from yolk sac larvae to adults of plaice, Pleuronectes platessa L. (Pisces: Pleuronectidae) and Dover sole, Solea solea (L.) (Pisces: Soleidae) was examined using scanning electron microscopy (SEM). Two ciliated cell types and a microvillar cell are present in both species soon after hatching and persist into adulthood. In juveniles and adults of plaice, there were significantly higher densities of ciliated sensory cells in the eyed side of the fish than in the blind side over all regions of the olfactory lamellae. Densities of microvillar cells were an order of magnitude less than those of ciliated cells in regions on the wider part of the lamellae, with no significant difference between organs in most of these regions. On the narrow part of the lamellae, densities of microvillar cells were significantly higher than on the wide part, and significantly higher in the eyed side organ. In sole, ciliated cells were significantly more dense in the blind side organ in three of the four regions examined in this species. In contrast, microvillar cells showed a similar pattern to that in plaice, being significantly more dense in the eyed side organ in two of the four regions. Comparisons between the species showed significantly higher densities of both cell types in sole, microvillar cells being an order of magnitude denser in comparable regions on the lamellae. In addition, the total area of the olfactory lamellae is around three times greater in sole. These data point to a possible morphological basis for the enhanced olfactory capabilities of sole apparent from behavioural studies.

Otolith microstructure analysis was used to reveal daily growth patterns of young-of-the year (YOY) of six species of perciform fishes, Bovichtus chilensis (Bovichtidae), Girella laevifrons and Graus nigra (Kyphosidae), Helcogrammoides chilensis (Tripterygiidae) and Hypsoblennius sordidus and Scartichthys viridis (Blenniidae). YOY collected in intertidal pools from June to December 2008 in Central Chile, ranged from 24 to 76 mm total length and from 25 to 390 days of age. In the six species, sagittal otoliths showed a slightly oval shape, symmetrical and laterally compressed and showed micro-increments distinguishable after a two-side polishing. Increment width of sagittae showed two patterns irrespective of hatch month and species: (i) a parabolic growth with wider increment widths (during the first 150 of YOY life, e.g. B. chilensis, G. nigra and G. laevifrons); and (ii) a more irregular pattern with lower increment widths during most of the seasons in H. chilensis and H. sordidus. Further results were: (i) a unique central primordium enclosed by two checks after which distinctive increments were deposited; (ii) low instantaneous growth rates estimated through the slope of the length-at-age relationship (range 0.1–0.21 mm d−1); and (iii) a linear fish size–otolith size relationship.

Alterations of the biochemical composition and survival of the rotifer Brachionus plicatilis have been investigated. During starvation the proportion of total protein increased from 45·3 to 62·7% while that of total lipid, carbohydrate and glycogen decreased from 20·1 to 6·9%, from 21·2 to 14·1% and from 17·3 to 4·9% dry weight, respectively. The proportion of polar lipids and free sterols in total lipids increased, from 8·3 to 32·0% and from 29·2 to 58·3% whereas triacylglycerol decreased from 54·7 to 4·2% dry weight. The most abrupt alteration in these fractions took place in the interval from 24 to 48 h. The proportion of monoacylglycerols, diacylglycerols, free fatty acids and esters of waxes and sterols in-creased from 1·2 to 3·0% (72 h), from 0·2 to 1·8 (48 h), from 0·7 to 2·4 (72 h) and from 5·7 to 12·1% (48 h) and then decreased to the level of 1·1, 0·9, 1·2 and 1·3%, respectively.

In 1954 and 1955 various natural, artificial and treated sea waters were tested with developing eggs of Echinus esculentus. The following are the main observations:

1. Sea waters filtered through Doulton candles at the time of collection and proved bacteriologically sterile until use were very little different from sea waters collected at the same time in the ordinary way and not sterile. (Expts. 1, 3, 8 and, with qualifications, 6.)

2. Undiluted Celtic sea bottom water and undiluted Celtic mud ‘extract’ were harmful to the eggs, but small volumes of both added to natural sea waters and to artificial sea water had a stimulating effect. (Expt. 1.)

3. In water from near the bottom at E1 eggs did worse, in 1954, than in surface water from the same locality. In 1955 they did slightly better in the deeper water. (Expts. 3, 4 and 7.)

4. Eggs placed immediately after fertilization in water from near the bottom at E1 (and from near the bottom at the Echinus ground) and transferred at first cleavage to surface waters were affected unfavourably. (Expts. 3, 4 and 7.) Artificial sea water had no such effect. (Expt. 5.)

5. The addition to natural and to artificial sea waters of filtrates from culture medium (‘erdschreiber’) and from thick cultures of diatoms and flagellates had no significant effects on the eggs developing in those waters. (Expt. 6.)

6. In 1955 surface water from the Clyde was a better medium for development than surface water from E1. The difference was similar to that frequently observed several years previously. (Expt. 7.)

7. Extracts of natural sea waters made by a new process were non-poisonous, but the experiment in which they were added to artificial sea water was inconclusive owing to the eggs proving to be of poor quality. (Expt. 8.)

The impact of biofouling by the filamentous bacteria Leucothrix mucor upon the body density and swimming behaviour of the harpacticoid copepod Tigriopus brevicornis was investigated. Biofouled individuals had a greater body density than non-fouled individuals. Biofouled and non-fouled animals swam similar distances and for similar periods of time during trials, but biofouled animals engaged in fewer, but longer bouts of swimming per trial and as a result experienced a lower swimming rate. These observations imply that biofouling has significant implications for the behavioural ecology of T. brevicornis.

Mesophotic coral ecosystems (MCEs) are found on the insular and continental slopes of Caribbean islands and comprise mainly scleractinian corals, sponges and macroalgae. These species provide habitat for a highly diverse and specialized crustacean fauna. A new genus and species of the family Louriniidae is described from samples taken from an MCE in south-west Puerto Rico. The new taxa can be diagnosed by: body elongate, almost cylindrical and with inconspicuous podoplean boundary between prosome and urosome; double genital somite with a discontinuous chitinized cuticular ridge; telson short with rectangular anal operculum; furca short; rostrum sinusoidal, well defined at the base; antennules 7-segmented with aesthetasc on the fourth segment; antenna with a brush-like basal seta and an abexopodal seta, exopod 1-segmented with 2 setae; endopod with 7 elements (1 geniculate seta and 1 modified inner spine); maxilliped well developed, prehensile, composed of syncoxa, basis, one segmented endopod and one claw-like apical seta; leg 1 endopod 3-segmented, first segment with a modified inner seta; legs 2, 3 and 4 with 2-segmented endopod with inner seta on the first segment; leg 5 basendopod fused, well developed with 4 setae, exopod well developed, with 5 setae; leg 6 represented by a single seta; and genital slits wide apart. The new genus and species can be confidently assigned to the family Louriniidae on the basis of the following synapomorphies: rostrum well-developed with rounded tip; antennule of female 7-segmented; mandible palp reduced; maxillule endopod and exopod absent; maxillae endopodite 2 represented by 3 setae; leg 5 basoendopod of female confluent, intercoxal sclerite absent, exopod 1-segmented; eggs retained in a single ventral egg sac; telson shorter than last urosomite; and furca short and with 6 setae.

1. The diphenylbenzidine reaction of Letts and Rea has been examined and is recommended for use in sea-water; 2·5 ml. of sea-water is mixed with 6·0 ml. of the purest strong sulphuric acid and then allowed to cool. Subsequently 1·5 ml. of a sulphuric acid solution of diphenylbenzidine is added, the concentration being 20 mg. per 100 ml. of acid. The colour should be compared, after 20-24 hours, with a standard solution made up by adding a definite quantity of nitrate to the sea-water. A blank correction should be used. Diphenylbenzidine used must be recrystallised from boiling toluene.

2. If the sulphuric acid used is found to give a blue colour with diphenylbeniddine, this may be removed, if not too intense, by warming the acid for a few minutes. With a more intense blue the nitric acid-present may be eliminated by previous cautious treatment with hydrogen sulphide. Phosphoric acid may be used instead of sulphuric acid with fresh water, but not with sea-water.

The overriding metabolic advantages of aerobic as compared with anaerobic respiration have resulted in its use by the majority of multicellular organisms. However, in some habitats oxygen is limiting to such an extent that anaerobic respiration becomes a necessity for survival. It has frequently been demonstrated that the extent of anaerobiosis depends, obviously, on the degree of oxygenation of the environment (see reviews by von Brand, 1944, 1945; Beadle, 1961). Hence, not only are there entirely anaerobic organisms but many other organisms exist which, in times of anoxic stress, are able to undergo a partial, or facultative, anaerobiosis. Lindeman (1942) discovered that, at low temperature, aquatic chironomid larvae could survive the entire winter anaerobically in the anoxic hypolimnion of freshwater lakes. Similarly, but to a lesser extent, pond-living crayfish of the genus Cambarus are more resistant to low oxygen concentration than stream-living individuals (Park, 1945). Walshe (1948) has also been able to establish a similar relationship in a group of stream and ditch dwelling chironomid larvae.

We evaluated sea urchin Strongylocentrotus droebachiensis predation on egg masses of the whelk Buccinum undatum. The urchin actively grazes on the egg masses, even as they are being deposited on the bottom. Whelks preferentially lay their egg masses on vertical areas where urchin densities are 4-fold less than on flat areas. This strategy is advantageous, as experimental trials showed that the loss in the mass of capsules was 4 fewer on walls than on flat areas. Nevertheless, a high proportion of egg masses on walls show damage from predation. Urchins provided with egg masses in the laboratory, ingested the capsules at a steady rate over a 9-d period (5 urchins ingested 2.8 g.d-1). Urchins provided agar discs that included a preferred alga and whelk capsule walls ingested the discs at a rate that was half that observed for discs that only included the alga. Discs that included the preferred alga and capsule contents were eaten at the same rate as discs that only included the alga. Thus, capsule walls, but not the capsule contents, provide a defence against urchin predation. Laying aggregate egg masses likely provides only a limited advantage, as the attachment surface does not increase with the number of egg masses deposited together, so the risk of detachment increases. Consideration of the interactions between urchins and whelks is important in managing the fisheries of the two species.

From bathyal depths in the Bay of Biscay, southwest of the British Isles, 89 species of polychaetes are described, among which are two new species, one new genus, and one new Combination, i.e. Pholoe fauveli sp. nov., Paracapitella southwardi n.gen., n. sp., and Galathowenia oculata, new combination. Of the species taken, 52 % are also known from abyssal depths. The bathyal polychaete fauna of the North Atlantic seems to be common with that of the Arctic and the North Pacific.

Larvae of eight sea spiders from three families (Ammotheidae, Pycnogonidae and Phoxichilidiidae) are described for the first time. The external morphology of the first larval stage of each species is presented in detail using scanning electron microscopy photographs in order to determine the mode of postembryonic development. Three types of larval development are apparent in the species examined. The species Achelia gracilipes, Eurycyde spinosa, Pycnogonum rickettsi and Pycnogonum stearnsi (families Ammotheidae and Pycnogonidae) have larval morphologies indicative of an ‘ectoparasitic’ development. Morphological characteristics of Achelia simplissima and Achelia chelata (family Ammotheidae) larvae suggest an ‘endoparasitic’ development, while larvae of the species Anoplodactylus viridintestinalis (family Phoxichilidiidae) have traits implying an ‘encysting’ postembryonic mode of development. Larvae of the species Nymphopsis spinosissima have unusual morphological characteristics that may be indicative of a new developmental mode.

Feeding, as estimated by egestion rate, in coastal epibenthic mud snails Hydrobia ulvae living continually submerged in lagoon-like conditions varies significantly with time of day. Both in the field and in the laboratory, egestion rate is maximal around mid-day and minimal at twilight. This variation, here ranging in magnitude from mean lows of some nine faecal pellets h−1 to highs of 34 h−1, is consonant with likely rhythms of availability and productivity of their microphytobenthic food.

Interannual and seasonal variation in recruitment of serpulid tube worms was monitored at two depths at each of four sites between February 1999 and January 2001 in Bantry Bay, Ireland. In both years, a single peak in recruitment was observed. The timing of the peak was similar in both years, but the magnitude of the peak differed significantly. More individuals recruited onto the underside than on the upperside of the horizontally orientated panels. A higher density of recruits was observed at a depth of 7 m than at 4 m during recruitment maxima. There was little variability in recruitment rates either within or between sites. The proportions of Pomatoceros triqueter and P. lamarckii recruiting per deployment were examined. Juvenile mortality was high. Based on ongrowing laboratory experiments, the dominant species was P. lamarckii. Serpula vermicularis was also present in low abundance. Examination of the spatial patterns of distribution of the serpulids indicated that the recruits were aggregated within panels. The degree of aggregation was correlated with the overall density of recruitment per panel.

Two benthic Rhodophyta, Ceramium pedicellatwn and Neogardhiella baileyi, were cultured in the laboratory to investigate uptake and subsequent release of Cu by both living and decomposing thalli. Concentration factors of Cu in the thalli of 4540-6864 were obtained. Algae grown initially in copper-supplemented media were cultured for 7 days in organic free medium and the amounts of Cu associated with the dissolved inorganic and organic fractions were then determined.

Occasional reference to the sporadic appearances of silicoflagellates (commonly Dictyocha spp.) are to be found in a number of seasonal studies of phytoplankton in the coastal waters of the British Isles. The silicoflagellates are rarely described in any detail since they usually form a small component of the annual phytoplankton. The autumnal occurrence of silicoflagellates in the Firth of Clyde was briefly described by Marshall (1924) in an account of the food of Calanus, and further seasonal observations on silicoflagellates in European coastal waters are to be found in the works of Margalef (1965), Nival (1965), Travers & Travers (1968) and Ignatiades (1970). Numerous studies on silicoflagellates have been concerned with their taxonomy, particularly the plasticity of form shown by their tubular siliceous skeletal structures and the many taxa (fossil and living) so far described. The confusion which has arisen through the differing views of palaeontologists studying fossil material, and botanists working with live populations and their seasonal abundances, has been highlighted recently in a culture study of Dictyocha fibula, in which skeletal variations in a single clone were matched with a number of other entities, fossil and living (Van Valkenburg & Norris, 1970).

Regeneration of the siphons of normal specimens Ciona intestinalis has been found to be completed, in every particular other than that of length, in 4 days.

Removal of the neuroglandular complex retards the regeneration rate.

With the exception of the epidermis and of the basic tunic, the new structures differentiate from haemoblasts.

A tentative synthesis has been made of the information available upon asexual reproduction and regeneration in the Ascidiaceae.

Corystes cassivelaunus is a crab of unusually narrow and elongated form, which has received the popular name of “masked crab” from the grotesque resemblance which its sculptured carapace bears to a human face. It is common round all the coasts of the British Isles, and, although normally an inhabitant of the deeper water, is occasionally found at home in sandy pools on the sea shore, and is frequently cast up in hundreds on sandy shores after heavy gales.