By the death at the age of 84 of Mr William H. Searle there passed away, on 6 April i960, one who had served the Laboratory longer than anyone else and who, during his 63 years as fisherman-collector, had installed himself in the affections of countless biologists the world over. From December 1895 until his retirement on 30 September 1958 his assiduous and unwearied devotion to his collecting duties, year in and year out whatever the weather, on the shore or in his boats, earned him the lasting gratitude of all those innumerable research workers, teachers and students who relied on ‘Bill’ to procure living material for their researches or studies. He, more than anyone else, knew where the animals were to be found, how to capture them without damage and how to ensure their safe arrival at the Laboratory hours later. More than one student who had been collecting on the shore alongside Bill has later been astonished to observe the large and varied assortment of creatures emerging alive and kicking from one small and tightly packed basket. He had a keen eye for the little things—Gromia, praniza larvae and the like, from the rock crevices he split open with his crow-bar. These he would carefully transfer from silted rock surface to honey jar on the point of his pocket-knife. He knew well their scientific names, though foreigners would often have difficulty in recognizing them when pronounced with a strong Devonshire accent. It was usually the old names current during his youth that he knew, and he was not alone in deploring the activities of systematists in so frequently changing and re-changing so many of them.

Nerve cells evidently of a sensory nature have been found in Eledone cirrhosa on the inside of the mantle in a limited area near the stellate ganglion. The cells, whose number on each side of the body is no less than 50, are in close association with a special thin layer of muscles, and obviously must have a proprioceptive function. The whole complex can therefore be regarded as a muscle receptor which from its situation may be termed the substellar organ.

The muscular component of this organ consists of fibres arranged in very flat bundles which, anastomosing with one another, form a plexiform layer situated under the stellate ganglion and the stellar nerves. It may be called substellar muscle plexus (ss-plexus for short). The area occupied by it, which is roughly semicircular in shape, extends to the points where the stellar nerves penetrate the muscles or a little beyond these points (Text-fig. 1). The ss-plexus, although situated close to thecompact muscle of the mantle, does not appear to have anatomical relation with the latter; it has, however, direct connexions with strands of muscle fibres reaching theplexus from two directions. The fibres coming from the medianside belong to the muscle attaching the mantle to the visceral sac in which runs the pallial nerve (or mantle connective). This muscle, called lateral pallial adductor (see Tippmar, 1913) istwisted in such a way that its bundles coming from the anterior region of the visceral sac insert into the mantle behind the stellate ganglion, and those originating posteriorly insert in front of it.

Studies by many workers on the subtle ecological relationships of marine organisms suggest that the distribution of these organisms may be controlled, at least in part, by trace organic substances in their environment. These substances may range from ‘toxins to vitamins and hormones’ (Lucas, 1955). Saunders (1957) has reviewed the interrelations ofdissolved organic matter and phytoplankton and considered the possible roles of organic metabolites in the growth of the algae. The presence of several vitamins, for example, B12, thiamin, niacin and biotin, has been demonstrated in natural waters, but the possible occurrence of plant hormones has not previously been considered.

In a recent paper (Allen, 1958) the ligament of Cochlodesma praetenue (Pulteney) as shown to have unusual features, the significance of which was not appreciated at that time. Examination of its structure shows that a further description is necessary.

Studies by Owen, Trueman & Yonge (1953), Owen (1958,1959), and Yonge (1953, 1957) have made clear the basic structure of the ligament of the adult bivalve. Primarily the ligament is composed of an inner layer covered by the anterior andposterior outer layers and the periostracum. The inner layer is secreted by the epithelium of the mantle isthmus, the outer layers are secreted by the outer surface of the outer mantle fold within the depths of the mantle embayments at either end of the mantle isthmus, and the periostracum is secreted by the inner surface of the outer mantle fold. This primary ligament may be secondarily extended anteriorly and/or posteriorly by fusion of the mantle margins and may involve extension by periostracum, or extension by fusion layer.

In a series of papers dealing with changes in the distribution of intertidal animals around Britain, and especially along the English Channel, attention was drawn to some local aspects of the general warming-up of sea and air that has taken place in the last 50 years (Southward & Crisp, 1954, 1956; Crisp and Southward, 1958). In the first of these papers smoothed values of annual mean air temperature at Plymouth Hoe, and sea surface temperature of the southern Celtic Sea were given, the latter values being based on Smed (1952). The graphs showed a rise of about 1° C in the air temperature and 0·5° C in sea temperature during 50 years.

The Megathyridae Allan 1940 is a family of brachiopods in which the adult lophophore is of simple design, bilobed (schizolophous) in Argyrotheca and four-lobed (ptycholophous) inMegathyris. Little is known of feeding mechanisms in the family. H´erouard (1877), finding it difficult or impossible to observe the feeding currents of living brachiopods, constructed artificial lophophores of lead piping with fine perforations corresponding to the position of attachment of the filaments. Through these he forced water, while the artificial lophophores were immersed in a bowl of water. He assumed, wrongly, that the result would be similar to the action produced by cilia vibrating in water. His remarks on the working of an artificial lophophore resembling that ofMegathyris (=Argiope) were transcribed by Morgan (1883) without making it clear that the observations were not his own and were not made on the living animal. Apart from HÉerouard's work on artificial lophophores, the only reference to feeding in a member of the Megathyridae is that of Shipley (1883) who merely mentioned that inArgyrotheca the arrangement of the cilia is adapted to bring particles into the ciliated groove and thence to the mouth. Thus an examination of the method of feeding of the Megathyridae was considered desirable, and was made possible in the first instance through the kindness of M. Paul Bourgis, then, in 1955, on the staff of the Laboratoire Arago, Banyuls-surMer. He sent two small consignments of livingArgyrotheca cor data (Risso),A. cuneata (Risso) andMegathyris detruncata (Gmelin), received on the 28 October and 24 December 1955.

Since November 1954, the natant epifauna in depths greater than 20 fm. off the Northumberland coast has been sampled at a number of stations with the object of obtaining information on its constitution and fluctuations. The survey has been limited to those species caught with a net of f in. mesh. Seasonal and yearly fluctuations in this fauna must have a considerable effect on the inshore fisheries, for these animals form an important part of the food of marketable fish, yet, this fauna has never beensubject to a detailed analysis over a number of years.

Samples have been taken as regularly as weather and other laboratory commitments have allowed. In practice this has been of the order of one sample each month, butat times sampling has been more frequent than this (Table 8). Although sampling is being continued, the material collected so far gives much information on the epifaunaas a whole and the biology of the constituent natant Crustacea and Mollusca.

Carlisle (1954) described Styela mammiculata, a new species of stalked ascidian from the Plymouth area, and suggested that it had been brought into British waters, probably with oysters. Its recent discovery on other parts of the south coast of England (Houghton & Millar, 1960) supports the idea that it is an introduced species which is now spreading through a favourable environment. It is well, therefore, to consider whether this may not be a species known from another part of the world. Tokioka (1955) examined one of Carlisle's specimens and suggested that it fell within the range of variation of S. clava Herdman. As many specimens of S.mammiculata are now available, a more extensive comparison has been made and is reported in this paper.

It is now known that organic binding of iodine takes place in the endostyle of Ciona (Barrington, 1957) and Amphioxus (Thomas, 1956; Barrington, 1958), and there isevidence that at least di-iodotyrosine and thyroxine are formed as a result of this processin Ciona (Barrington, 1959; Robertson, personal communication. Since this biosynthesis appears to be a specialized property of a restricted group of cells, it has been suggested (Barrington, 1959) that it is not a chance by-product of endostylar secretion but that the thyroidal products are a biochemical necessity for the animals concerned. Attention has been drawn also to the occurrence of iodine binding at the surface of the tunic (or test) of Ciona (Barrington, 1957), and it is the purpose of the present paper to present some analysis of this latter situation and to enquire as to its possible relationship with the endostylar activity.

Analyses of sea water collected during 1959 at the International Hydrographic Station E1 (lat. 50° 02′ N., long. 4° 22′ W.) are given here in the same form as earlier reports (Armstrong, 1954, 1955, 1957, 1958; Armstrong & Butler, 1959, 1960). The methods of collection and analysis remain the same. Salinities were determined by the Government Chemist, Department of Scientific and Industrial Research. We wish once more to thank Lt.-Cdr. C. A. Hoodless, D.S.C. and the crew of R.V. ‘Sarsia’, and Capt. W. J. Creese and the crew of R.V. ‘Sula’ for help at sea.

Many stomiatoid fishes possess a peculiar light-organ below and behind the eye, as well as other kinds of photophores. This light-organ, of diagnostic importance, is termed the subocular, postocular or cheek-organ. Stomiatoid fishes, suborder Stomiatoidei, form a suborder of the Isospondyli. Subocularorgans are found in the following groups:

In the last few years the exceptionally large monothalamous arenaceous rhizopod,Astrorhiza limicola Sandahl, 1858, has been collected in appreciable numbers from the Blythand Plymouth areas of British coastal waters. These collections of the living animals have enabled the authors, both independently and jointly, to make certain observations of the behaviour of the animal, and of the structure of the test, which have not been appreciated hitherto. With the exception of two early accountsof A.limicola, one by Bessels (1875) under the name Haeckelina gigantea and the other by Schultz (1915), very little appears to be known of the biology ofany member of the family Astrorhizidae.

Electric rays (Torpedinidae) are known to harbour on their gills certain monogenean parasites (Amphibdella spp. and Amphibdelloides spp.) whose taxonomy is in a very confused state. Muchof this confusion has centred around a single morphological feature: a ‘transverse bar’ has been variously held to be present or absent from the adhesive apparatus, or sometimes two such bars have been stated to be present. Among those who have regarded the trans-verse bar as having taxonomic importance, Price (1937) recognized two genera of amphibdellids distinguishable by the presence or absence of the bar, but Palombi (1949) and Bychowsky (1957) believe that the bar may be present in young specimens but absent or inconspicuous in older specimens. No-one has investigated the function of thistransverse bar, or, indeed, any functional aspect of the adhesive apparatus. Again little attention has been paid in taxonomy to the genitalia or host specificity, or, in spite of a record of an amphibdellid from the heart of its host, to micro-habitat.

The herring(Clupea harengus L.) deposits its eggs in the coastal waters around the North Atlantic Ocean, North Sea, and Baltic Sea. The salinity on the spawning grounds may vary from about 35%0 to 5%0. For instance, Brandhorst (1959) reports that successful spawning tookplace in the Kiel Canal in salinities down to 5%0, and Ford (1929) records that ripe herring have been found in the Tamar estuary. In a series of experiments Ford found that the eggs of herring could be successfully fertilized and incubated even in a salinity of 4·8%0. McMynn & Hoar (1953) investigated the effect of salinity on the development of the Pacific herringC. pallasii and found it had a wide tolerance, the lower level being somewhere between o and 6‰

Most of the work on temperatures lethal to fish has been reviewed by Brett (1956). Most of the fish have been adults of freshwater species, and it has been found that both upper and lower lethal temperatures vary with the species, the temperature of acclimatization and the duration of time the fish are subjected to the test temperature.

The recent spread of the free-diving technique has made direct contact with the sublittoral environment relatively simple. The advantages of this to the ecologist need not be stressed.

The rather more cumbersome and expensive standard diving method had had already been used by Gislén (1930), Kitching, Macan & Gilson (1934), Kitching (1937, 1941), Zalokar (1942), Bursa, Wojtusiak & Wojtusiak (1948) and Waern (1952). Drach (1948 a,b, 1949, 1951) was the first to exploit free diving for ecological purposes and was followed by Forster (1954, 1955, 1958), Pérès & Piccard (1949), Ernst (1955), Laborel & Vacelet (1958), Knight-Jones & Clifford Jones (1956) and Aleem (1956).

Codium amphibium was described by Harvey (1844) on the basis of material sent to him by David Moore, who in turn had received it from the collector, William M'Calla. This material was said to grow 'on turfy banks at extreme high-water mark, near Roundstone, county Galway', and was described as comprising numerous erect, small (to 1/4 in. high), simple, cylindrical or subclavate, obtuse fronds arising from a mass of entangled, divaricately branched filaments densely aggregated into widely spreading patches. Harvey's illustration clearly shows the habit, but his drawing of utricles is neither diagnostic nor accurate [as judged from our study of the type material]. Harvey made particular note of the habitat, which he inferred would place the plant 'beyond the reach of the ordinary sea-level'. In a later work, Harvey (1846, pi. 35 B) illustrated this species with similar drawings and added nothing to the description except to extend the maximum height of the fronds to 'nearly half an inch'. Still later, Harvey (1849, p. 194) increased the maximum height of the fronds to an inch, modified ' simple' to ' usually simple, rarely emarginate or forked', added the locality 'at the head of Birtirbui Bay, Galway' and changed the habitat as follows: 'Turf banks, near high-water mark, but washed by every tide...' Kiitzing (1849, p. 502) furnished a description similar to the original one, based on an Irish specimen sent to him by Berkeley, probably topotype material. In his illustration of this material, Kiitzing (1856, pi. 96, fig. a) snowed an important character of the utricles: a tendency towards pointed apices.

An understanding of the oceanography of the Celtic Sea requires anunder-standing of the exchanges of water around four headlands, Ushant, Lands End, St Davids Head and Carnsore Point. As a sequel to the study on the flow past Ushant already presented (Cooper, 1960b), this paper and the following one by Cooper, Lawford & Veley are attempts to achieve a better understanding of the exchanges around Lands End andin the neighbourhood of the Scilly Isles (Fig. 1).

Matthews (1914, p. 20) said: 'The charts published in this report show that the saltest water enters the Irish area between Lands End and the Scilly Islands, and detailed observations made along this line on several cruises at intervals of from half a mile to one mile onthe Marine Biological Association's steamers have shown that the axis of highest salinity lies midway between the Longships Rock and the Seven Stones Lightship, that is, at a distance of only a few miles off Lands End. This current of salt warm water is derived from a current which has already entered the English Channel from a southwesterly direction, and has in part turned northwards and north-westwards to escape into the Irish Channel. It is practically certain that this water has come from the mouth of the English Channel and not directly from the open sea because further westwards a great area of lower surface salinity stretches southwards across the fairway and prevents any such direct current.' Harvey (1925, fig. 19) accepted Matthews' interpretation and later (1929) from a study of geopotential topographies deduced that a residual current ran between Lands End and the Scillies in June 1924 in a N.N.E. applies more nearly in the passage itself..

Measurements of current at the Seven Stones Light Vessel, 50° 03·5' N. lat., 6° 05·1' W. long. (for position, see Cooper, 1960b, fig. 1) were first made with the Carruthers Drift Indicator between 17 August and 15 September 1933 (Carruthers, 1934). The much longer series with the Vertical Log between July 1939 and April 1941 showed average travel of the residual cur-rent at a rate of 2·5 miles per day towards east-south-east (110° true) (Carruthers, Lawford & Veley, 1951). It was shown clearly that there was a strong causal connexion between the direction and strength of the wind and direction and strength of current, but that there were evidently other factors concerned as well. These current measurements were not easy to reconcile with deductions from the observed distributions of temperature and salinity in the area (Matthews, 1914; Harvey, 1925, 1929; Cooper, 19606). A rational explanation could be achieved if it is assumed that the passage of water from the English Channel to the Bristol Channel occurs intermittently and is confined to a narrow current close into Lands End. This ‘corner current’ rarely extends as far west as the Seven Stones Light Vessel.

Thorson (1946) considered in detail the earlier views of Appellöf (1912), Orton (1920) and Runnström (1928) that breeding activities of the majority of marine organisms were controlled by the temperature of the sea and referred to this as Orton's rule. RecentlyCrisp (1954) and Qasim (1956) also reviewed the existing literature on this subject in relation to barnacles and fish. By considering the seasonal availability of planktonic food in con-junction with Orton's rule, they explained why tropical species inhabiting cool temperate waters have a breeding season confined to the warmer months, whereas boreo-arctic species throughout their whole range breed only during colder months.