Oscular tubes were photomicrographed at intervals of roughly one or more days. The changes in length and width were determined using radiate spicules as markers. Changes in width were also measured directly using the outlines of the tubes. Several types of growth were thereby observed. The category considered here includes a temporary phase of constriction during the interval between the photographs. Such irregular growth is usual for Leucosolenia situated in rock pools on the shore.

Dead and dying fish were reported from the Moray Firth during a period of 15 days in September 1963. The initial mortalities were in the inner Firth, but they later spread outwards, especially eastwards along the southern shores of the Firth. Mass mortalities of the lugworm (Arenicola marina) also occurred in Scottish waters in 1962 and 1963, and at Balintorein Easter Ross fish and lugworm mortalities were contemporary.

Adult Pseudocalanus elongatus have been kept in the laboratory, and fed with a variety of algal grazing media. The survival under conditions of starvation has also been determined, and in this respect, the overwintering generation has been found to differ from other generations.

Isochrysis galbana, Phaeodactylum tricornutum, Gymnodinium veneficum, G. vitiligo, Chlamydomonas sp. and C. coccoides have been found to be satisfactory foods for Pseudocalanus elongatus

Dicrateria inornata, Nitzschia gotlandica, Amphidinium sp., Chlorella stigmatophora and Dunaliella tertiolecta were found to be unsatisfactory foods for Pseudocalanus elongatus.

The polychaete worms Cirratulus cirratus and Cirriformia tentaculata harbour a number of archigregarines which have frequently been confused in the past. An attempt is made to clarify the situation and a new parasite, Ditrypanocystis cirratuli, previously described only from C. tentaculata from St Andrews, is recorded from C. cirratus from Plymouth and described. The nomenclature of the archigregarines from C. cirratus is discussed.

Inactive Mn concentrations have been measured in lobster tissues. In the internal tissues of fresh animals, muscle contains 0.5–1.1 μg/g wet tissue, hepatopancreas contains 4.1–5.7 μg/g, excretory organs contain 2–5.5 μg/g and the blood contains 1.4–3.8 μg/g. Gill Mn concentrations are very variable and up to 30 μg/g are found. About 98 % of the Mn in the body lies in the calcified exoskeleton. Concentrations in the carapace are variable and are of the order of 100–300 μg/g of wet tissue. Possible ways in which the body Mn content may be controlled have been studied.

Manganese is lost from the blood during starvation and is absorbed so slowly from solution in sea water that normally an appreciable amount of the body Mn must be absorbed from food. Absorption from the stomach takes place via the hepatopancreas and the amount absorbed appears to be proportional to the Mn concentration of the stomach fluid. Similarly, there is no evidence that the slow absorption of Mn from solution in sea water across the gills can in any way be controlled and it may be a passive rather than an active process.

The absorption of radioactive Cs from sea water in relation to K metabolism has been examined in the squat lobster Galathea squamifera. A general study has been made of the ability of Galathea to carry out osmotic and ionic regulation as a comparison with better known decapod crustaceans which have previously been used for radioactive Cs experiments.

Galathea appears to be a truly marine decapod in that it is probably unable to osmoregulate and the body surface is very permeable to water and to Cs and Kions. Despite this high permeability, Galathea is able to regulate K and radioactive Cs at blood plasma levels which are 1.3 and 1.1 times those of sea water. The Na and Cl concentrations in the plasma are not regulated and the Ca concentration is variable, but Mg and SO4 are maintained at concentrations below those of sea water. Urinary excretion does not assist in the conservation of K or radioactive Cs in the plasma but assists in removing Mg and SO4.

In North Wales settlement and metamorphosis of Balanus balanoides occur in May and the animals breed for the first time in the following November. Three weeks after metamorphosis the oviducal glands appear as epidermal invaginations in the basal segments of the first pair of cirri. At first there is no lumen or external duct but these develop during the next fortnight. The wall of the gland is a columnar epithelium which increases in height as the gland increases in size. During mitosis this epithelium exhibits the pattern of cell movements characteristic of similar epithelia in vertebrate embryos.

Sporophytes of Laminaria hyperborea have been grown under various conditions in the laboratory up to the stage of 1000 cells. Some larger plants have been observed after exposure in the sea. Growth was not increased by artificial aeration of the normally stagnant cultures, nor by introducing a dark period each day. The cell number per sporophyte was found to increase exponentially with time. In from 10- to 1000-celled plants the logarithm of the cell number was proportional to the logarithm of the plant length; the relationship corresponded to two-dimensional growth in the presence of increase in cell length. In this size range, when the plants were mainly monostromatic, the growth rate in the laboratory was 0.5 cell divisions/day and 22% increase in length/day. The growth rate of larger sporophytes, partly polystromatic, in the sea, was 10% increase in length/day. A sporophyte would take at least 54 days from the release of the parent zoospores to reach a length of 1 cm. The minimum continuous irradiance necessary for growth was 2 μg.cal/cm2sec (20 lux) at 10° C and 4–5μg.cal/cm2sec (40–50 lux) at 17° C. The saturating continuous irradiance was at about 100 μg.cal/cm2sec (1000 lux) at 10° C and about 150 μg.cal/cm2sec (1500 lux) at 17° C. Up to 360 μg.cal/cm2sec (3600 lux) from fluorescent lamps was not inhibitory. Growth at 15–20° C was approximately the same as at io° C.

The respiration of Limnoria was measured manometrically in sixteen solutions ranging from 6% to full strength sea water (36%). In a second series of experiments, simultaneous measurements were made in full strength sea water and in dilutions of 7, 14, 21 and 28% respectively. No significant correlation was found between the respiratory rate and the degree of dilution of the medium.

Details are presented here of four species of amphipod from Norfolk waters, including descriptions of Melita reidi sp.nov. and of Parapleustes sp., as well as comments upon an unusual young Siphonoecetes sp., and on a population of Amphilochus spencebatei. The Melita is very small, pale and blind, and apparently lives interstitially.

During a study of the amphipods of Norfolk (in preparation for publication) a species of amphipod apparently new to science has been found, and is described below; comments are also made here on the taxonomic characters of three other species found locally. The area concerned (including a station list) is described by Hamond (1963).

Records of cirral activity have been made over periods of 24–48 h for individual specimens of eight species of barnacles from three different localities. The effects of movement, gas content, and hydrogen-ion concentration of the water have been studied.

In still water most species eventually settle down to a more or less steady rhythm (activity rhythm) of short bursts of cirral beating interspersed with inactive periods. Two exceptions are the surf- or current-loving species Balanus cariosus and Tetraclita squamosa which remain inactive or eventually cease activity. In moving water all species show practically continuous activity, the velocity of the flow needed to produce this response varying according to the species, habitat, and previous history of the specimen. Increased oxygen content has less effect on activity than other factors studied, but eventually appears to reduce activity. A gradual reduction in oxygen content first leads to increased activity and then signs of distress attributable to anoxia.

The distributions of four species of larval Ammodytidae in the Southern North Sea are described. Two separate broods of Ammodytes lancea larvae were found, in spring and autumn. The spring larvae occurred in the areas of the Thames and Wash, and the autumn type mainly off the French and Dutch coasts.

A description of these larvae is given. Larvae of Gymnamtnodytes semisquamatus were found in the Southern Bight area and in several areas off the Humber. Few larvae of Ammodytes lanceolatus were taken: they occurred in the Southern Bight and Dowsing areas. A. marinus larvae were found in two areas off the Humber and in the Southern Bight. There is evidence for a spawning area some distance to the west of the Dover Strait.

A system of nerves (called for short NSV system), described previously in Eledone cirrosa, whose only task appears to be the formation of a fine neuropile in the vena cava, is present also in Sepia officinalis It has a similar disposition to that in Eledone but shows certain special features. It is composed of neurons the cell bodies of which are located in a layer (NSV layer) of the visceral lobe of the brain and in the paired ganglionic trunks, termed the lateral and medial NSV trunks, which emerge from the visceral lobe with the posterior infundibular and visceral nerves respectively. After accompanying these nerves for some distance these trunks take an independent course and give off some tapering branches ending blindly in the loose connective tissue.

Some marine ciliates, chiefly belonging to the genus Cothurnia are recorded from Plymouth and figured. Three new species are described.

Little has been published on the Ciliata from Plymouth waters. The publications of de Morgan (1925, 1926) alone provide a detailed description of some species. In the last edition of the Plymouth Marine Fauna (Marine Biological Assoc, 1957) many species have been recorded not described by de Morgan but which were occasionally mentioned in the works of other authors, and included those investigated by the present writer during her visits to the Plymouth Laboratory in the years 1953 to 1963. Recently, a list of Protozoa observed at Plymouth has been published by Lackey & Lackey (1963).

A light and electron microscopical study has been carried out on the morphology and microanatomy of two marine species of Heteromastix and less completely on two freshwater samples from the same genus, one only of which is named; this one is, however, important as the type species of the genus (H. angulata Korsh.). Agreement in salient features indicates that Bipedinomonas N. Carter andAnisomonas Butcher, under which the marine species were previously described, should be discarded as later synonyms of Heteromastix Korsh. Apart from the nomenclatural clarification the most important new findings concern the details of the periplast on cell body and flagella, the presence of stellate scales as well as plate-scales on both types of surface, the presence within the body of a starch shell not giving the normal colour reaction with iodine, and of a characteristic fibrous ‘root’ joining the flagellar bases to the plastid surface. A major finding of electron microscopical interest is the clarity with which the formation of scales and of flagellar hairs has been traced to the Golgi cisternae. These observations are an important addition to previous knowledge concerning genera of related green flagellates possibly referable to the class Prasinophyceae.

The preoccupation of many workers in recent years with the detailed analysis of the settlement behaviour of the larvae of numerous sedentary invertebrates has contributed significantly to our understanding of the various factors influencing the secondary orientation reactions of animals as formulated by Fraenkel & Gunn. Investigations with the planula larvae of hydroids along these lines has hitherto been largely ignored. The intertidal hydroid Clava squamata Müller has a distribution restricted to the larger fucoids in the littoral zone and during the summer months liberates its planulae in large numbers.

Detailed examination of the distribution of colonies indicated that the planulae probably possess clearly defined patterns of behaviour which assists them in locating substrates suitable for colonization. The planulae which are released in response to light are normally found to be photopositive on inert surfaces and to settle photopositively. On Ascophyllum, however, the normal substrate in nature, the older larvae are photonegative. The crawling activity of the planulae is considerably influenced by the texture and contour of surfaces. On rough and pitted surfaces activity is considerably reduced indicating a thigmokinetic response of the larvae. Water currents influence behaviour, planulae orientating positively to the direction of flow. The possible significance of these patterns of behaviour in the substrate selection and distribution of the species is discussed.

Evidence is presented that eggs and sperm of Spirorbis borealis are shed through the nephridioducts, and that fertilization occurs externally to the body but inside the tube.

The eggs fail to develop in vitro unless sperm is present. In individuals collected in winter and maintained at 15 or 19° C, the male and female gonads mature more or less simultaneously. Among groups of individuals sperm is usually shed first and soon afterwards a large proportion may be observed to have extruded ova.