Samples of the large sublittoral sea anemone Urticina eques (Gosse) were collected from three localities in the northern North Sea and from one locality in the northern Irish Sea. Around the coast the total distance between sampling sites is approximately 1,200 km. The species has a large lecithotrophic larva which may not be planktonic. All samples were screened genetically for 13 loci coding for 11 different enzymes. Results overall indicated a high degree of genetic uniformity over the four populations sampled (FST = 0·025). The data are discussed in relation to current ideas of larval dispersal and results from other similar studies. It is concluded that the lack of genetic differentiation shown by Urticina eques is surprising given the apparently poor dispersive powers of the larva.

Shell growth of the razor clam Ensis siliqua (Mollusca: Bivalvia) from southern Portugal has been analysed using both surface growth rings and internal shell microgrowth patterns. The growth rate estimated from an analysis of the growth rings is slower (von Bertalanffy growth, constant K=0·27) than that determined from the annual narrowing of the internal microgrowth patterns present in shell sections (K=0·65), although both methods predict a similar asymptotic length, L∞, of 144·8 and 139·6 mm, respectively.

The Barrinha razor clam population occurs in a heavily dredged area and an analysis of shell sections reveals the presence of a series of shell margin breaks consisting of deep clefts in the outer shell layer in which sand grains are embedded. It is suggested that these disturbances to shell growth are the result of repeated dredge damage. The frequency of the clefts increases with the size and age of the razor clams, and thus the shells provide a record of the intensity and frequency of unsuccessful capture or retrieval attempts. Cleft formation also occurred seasonally with the deposition of a small cleft during June, but these annual clefts were much less pronounced than those caused by dredge damage.

The functional morphology of the buccal mass of 23 species of cephalopod (Octopoda, 4 species; Teuthoidea, 17; Sepioidea, 2) was investigated by gross dissection, histology and observations on fresh preparations. Cephalopod beaks lack a joint or articulation point. The jaws slide and rotate around an area rather than a fixed point. During closing the superior mandibular muscle (SMM) provides the force of a bite and the largest movement vector, whilst the inferior mandibular muscle (IMM) acts to retract the upper beak, causing shearing action. Dorsal portions of the lateral mandibular muscles (LMM) flex the upper beak walls outwards, probably to accommodate the backwards sweep of the radula and buccal palps during closing. To open the beaks, the ventral portions of the lateral mandibular muscles pull the rear lateral walls of the two beaks towards each other, moving the lower beak back relative to the upper.

The cellular features of mercury and selenium accumulation has been studied by transmission electron microscopy and x-ray microprobe analysis in the liver of striped dolphins. Mercury and selenium occurred as dense intracellular granules, located mainly within the liver macrophages (Kupffer cells). Granules were composed of 150 A spherical particles showing the same electron diffraction pattern and x-ray spectrum as mercuric selenide. The role of macrophages in mercuric selenide granule production and storage is discussed.

Ligia italica Fabricius is a day-active isopod on the shores of Madeira. The population migrates up and down the shore with the tide, browsing on lichens and macroalgae. Shore bird predation is negligible; foraging wall lizards are the only daytime predators. Ligia italica retreats into crevices at night. It exploits plant material within supralittoral and intertidal pools and enters pools with salinities as high as 74‰. Ligia italica emerges from pools at intervals to breathe in air; such emersion lasts no more than two minutes. Ligia italica on Madeira has no colour change ability, the isopods remaining dark grey/black whatever the background.

Atlantic bonito, Sarda sarda, is one of the representatives of the Scombridae family in the Adriatic Sea. Larvae and juveniles have been found and described in the area, but no information has been published regarding adults spawning in the Adriatic Sea. To explore the strong possibility that Atlantic bonito are reproducing in the Adriatic Sea, 122 specimens of adult Atlantic bonito were collected from a purse seine net ‘palamidara’ over four seasons in 2017. The fork length of the analysed specimens varied from 37.5 to 60.8 cm, with a mean of 48.83 ± 5.59 cm, while total body weight varied between 742.68 and 3102.59 g, with a mean value of 1700.49 ± 543.82 g. Gonadosomatic index values showed an increasing trend from autumn (0.123 for males, 0.897 for females) until spring, while in the summer, they reached their maximum values (3.609 for males, 5.604 for females). This trend was also confirmed by histological and macroscopic analyses of gonads, which suggested that the Atlantic bonito spawning season is in the spring-summer in the Adriatic Sea. Hence, this confirms that this species is spawning in the Adriatic Sea.

The first record of the ophiuroid family Ophiohelidae from the Mediterranean Sea is reported. It consists of the description of the new record of Ophiomyces grandis from the Mallorca Channel seamounts in the Balearic Islands, western Mediterranean, where it shows high abundances. We present both the morphological description of the individuals collected and, for the first time, the cytochrome oxidase subunit I (COI) sequence of this species. The morphological traits of our specimens match the available descriptions of O. grandis. On the other hand, molecular analyses show a large genetic distance between O. grandis and Ophiomyces delata, the two species being very similar morphologically. Despite the high abundances of O. grandis reported here, previous surveys in the Mallorca Channel seamounts using ROV did not detect it, emphasizing the importance of beam trawl sampling to improving the biodiversity description of these geomorphological sea bottom features.