Terms, dimensions and ratios for statolith description are defined. The form of the calcareousstatoliths in the Teuthoidea, Sepiodea and Octopoda is described by reference to Loligo forbesi, Sepia officinalis and Eledone cirrosa. While statoliths change in form and size during the growth of a cephalopod, the adult form is often characteristic for a species, despite some variation. Description of statoliths is important in studies of the fossil remains of cephalopods lacking calcareous shells, and will probably become important in the taxonomy of living species, in food analysis of cephalopod predators and in the study of deep sea deposits.

This study of the genus Pterosperma followed on from our work on the genus Halosphaera (Parke & Adams, 1961; Parke & Hartog-Adams, 1965; Boalch & Mommaerts, 1969) since while studying the latter we found abundant pterospermatacean material. In recent books on algae the family Pterospermataceae Ostenfeld (1902) is placed in the class Chrysophyceae (Papenfuss, 1955; Bourrelly, 1957, 1968; Fott, 1959, 1971; Prescott, 1969). The family, however, rightfully belongs in the class Prasinophyceae (Parke in Parke & Dixon, 1964, 1968; Christensen, 1966) in the order Pterospermatales (Parke & Green in Parke & Dixon, 1976).

Various workers during the past century have figured sensory cells bearing cilia amongst the ordinary non-ciliated epidermal cells of the body surface. Similar sensory cells were also found on the buccal cirrhi, and on the velar tentacles at the entry to the atrium. This earlier work at the light microscope level was summarized by Franz (1923) in his excellent review. More recently Schulte & Riehl (1977) have re-examined the innervation of the oral region and buccal cirrhi at the ultrastructural level, and observed two types of sensory cell in these regions, distinguished by their apical structure. They suggest that these are both secondary sensory neurons (as Franz had previously surmised), but their figures hardly make this suggestion convincing. In this note we show that there is probably only a single type of sensory cell amongst the epidermal cells of the body surface and buccal cirrhi; that it synapses at its base with incoming axons of central cells, and that a different type is indeed found in amphioxus, but only in the velar tentacles.

The first species ofLamellisabella to be described from the Atlantic Ocean has rows of small teeth on the tentacles. It occurs at about 4000 m depth in the Bay of Biscay, and its range probably extends along the continental rise at least as far south as the Gulf of Guinea.

I trust that I will not be criticized for saying that, in general, the argument between Hensen and Haeckel has been resolved. Hensen (1887, 1895) believed that true spatial and temporal heterogeneity of the plankton could be resolved by careful measurement and analyses of variance. Haeckel (1893) thought these analyses might give more information than the data possessed. Our present understanding of spatial heterogeneity, and its analysis, does not lead us to disagree with either. Investigations carried out by a number of marine ecologists have shown large-scale spatial variations in phytoplankton. Amongst many others, this feature can be seen in studies off the northeast coast of England (Cushing, 1955), in the English Channel and Celtic Sea (Cushing, 1957; Pingree et al. 1976), off Scotland (Adams, Baird & Dunn, 1975,1976) and off the coast of the Netherlands (Gieskes & Kraay, 1975). Nevertheless the statistics of sampling heterogeneous distributions is far from simple, estimates of density for instance can be greatly influenced by the sample size (e.g. Greig-Smith, 1964; Cassie, 1963). Bainbridge (1957) summarized his review by saying that patches occurred on all scales from a few feet to as much as 30 or 40 miles by 120 or 180 miles. Our present understanding of the nature of turbulence in the sea would reduce his few feet to centimetres.

In order to improve their quality before commercial distribution, oysters in the Marennes-Oleron region of France are placed temporarily in sea water in either natural basins or artificial canals known as 'claires' (Korringa, 1976). It has been known for some time that these marine enclosures provide an environment particularly rich in a variety of micro-organisms many of which are valuable sources of food thus contributing to the growth of the oysters; one species in particular, the diatom Navicula ostrearia (Gaillon) Bory, gives them a green hue and a special flavour much appreciated by French consumers (Neuville & Daste, 1972). For some years, two of us (D.N and Ph. D.) have been concerned with detailed investigations of the diatoms of the 'claires', especially N. ostrearia (Daste & Neuville, 1976).

Plasma vitellogenin synthesis in adult female Scyliorhinus canicula L. continued throughout the year but the rate of synthesis was significantly lower between March and August than during the rest of the year. The hepatosomatic index (liver weight as percentage of body weight) underwent annual variation in both sexes but this variation was considerably more pronounced in the female. Increase in hepatosomatic index in the female was accompanied by increase in the percentage of lipid in the liver and was largely caused by increase in the total lipid content of the liver. Comparison of livers of males and females showed that the percentage of lipid was not significantly different while the percentage of solids insoluble in water and organic solvents was greater in the female. Oviposition, as indicated by the percentage of females with eggs in the oviducts, continued throughout the year, reaching a minimum in September-October. Between July and October, parameters associated with vitellogenesis began recovery from their respective annual minima in the following order: plasma oestradiol level, hepatosomatic index, rate of synthesis of plasma vitellogenin, gonosomatic index, plasma vitellogenin level, rate of oviposition.

Salpingoeca natans Grentved and 5. spinifera Throndsen have been removed from Salpingoeca James-Clark and made the nomenclatural types of Calliacantha gen.nov., and Bicosta gen.nov., respectively.

James-Clark (1876) erected the genus Salpingoeca J.-Clk, 1867 for solitary choanoflagellates with colourless, transparent, thecae.* As for most choanoflagellates the protoplasts possessed a single anterior flagellum surrounded by a hyaline collar which, when viewed with the light microscope, appeared membranous.

Activities of phosphomonoesterases were measured at acid and at alkaline reaction (pH 4–5 or 9–65) in homogenates of elasmobranch tissues especially lymphomyeloid structures. The animals were dogfish (Scyliorhinus caniculd) and two species of ray (Raja brachyura, R. naevus). Acid phosphatase activity was high in the epigonal tissue, Leydig's organ, the spleen and the thymus. High activity was also found in the pancreas and the kidney, whereas skeletal and cardiac muscle showed low values. The activity of alkaline phosphatase was very high in the kidney and relatively low in other tissues. Ultrasonification of homogenates from the dogfish resulted in increase of acid phosphatase activity but had little effect on alkaline phosphatase activity. The high activity of acid phosphatase in lymphomyeloid tissue may be due to the presence of large numbers of various types of leucocytes.

The family Ectocarpaceae currently contains the simplest, and probably also the most primitive, members of the Phaeophyceae. The thallus form of every species is a heterotrichous filament with little or no structural modification. Some species may possess quite extensive cortication of axial filaments by adventitious rhizoids but advanced pseudoparenchyma is never formed. Periclinal cell divisions within filaments have also been reported, particularly in the course of sporangium development, but true parenchyma is unknown. Growth of the erect system of filaments is diffuse, for although intercalary sites of relatively active cell division may sometimes be observed, these lack the permanence of position and sustained activity of true intercalary meristems. The growth of the horizontal branch system is probably mainly apical, but is also too diffuse to be considered meristematic. Sporangia and gametangia are formed from vegetative cells and occur either as intercalary structures within filaments or as modified branch apices. Sexual fusion of gametes may be isogamous or anisogamous.

Citadel Hill, Plymouth (Plates I–II) The sexual display and mating of the dragonet (Callionymus lyra L.) were well described by Holt in 1898 from observations of the behaviour in a relatively small tank in the Plymouth aquarium. When in 1959 numerous dragonets werekept in a much larger tank mature males established territories within which they displayed tofemales. The more pugnacious males maintained larger territories than less pugnacious males. Maintenance was mainly by display against rivals without physical contact, but occasionally there were direct attacks in which minor damage was inflicted.

In his long and detailed account of the sexual display and mating of the dragonet (Callionymus lyra L.), based on observations in the Association's aquarium at Plymouth, Holt (1898) makes no mention of males defending specific areas and states that there was 'no evidence of serious combat among mature males' (p. 312). 'Occasionally the two males meet in full splendour. Then one lowers his colours and flies ingloriously; but I have never seen anything in the shape of a fight, and have never found wounds that might have been inflicted when I was not watching' (p. 288). Holt records (p. 286) that his dragonets inhabited a tank on the south side of the aquarium and it was in that tank that breeding displays took place. He also put large males into a very much larger tank, though only to watch their reactions in the presence of large turbot (p. 295): one was eaten, others disappeared not to be seen again.