Colloidal ferric hydroxide flocculates in sea water, the less rapidly the greater the dilution. When formed in the presence of very small quantities of various emulsoids, it does not flocculate on adding to sea water or flocculates less rapidly.

An attempt has been made to give the range and rate of fluctuation of salinity (and, to a lesser extent, of temperature) that organisms experience at various points on the bed of the lower Tamar Estuary and in the overlying water especially near the surface. Such work until now does not seem to have been attempted. The following general facts emerge: On proceeding from high-water mark to low-water mark there is an increase in the range, rate and duration of fluctuation in salinity. Also the upper limit of the salinity range rises very slightly while the lower limit falls by a large amount, i.e. there is a more or less uniform gradient from high-water mark to low-water mark. Near high-water mark the fluctuation is less and of shorter incidence and is distributed over a higher level of the total salinity range (for the intertidal area) than near low-water mark. Owing to stratification, the farther down the intertidal area the (slightly) longer is the duration of the high salinities, especially in winter. At mid-tide mark the fluctuation is very similar to that on the bottom in mid-river, but is of twice the rate.

The question is raised how pelagic larvae of marine bottom animals reach a type of substratum suitable for adult life. Attention is drawn, to a few forms in which it is not entirely due to chance, since their larvae have been shown to exercise some degree of choice of the soil on which they will settle, and to be capable of preserving the ability to metamorphose for several days at least. These powers, if found to be fairly general in marine bottom animals, would have important bearings on distribution problems. There is supporting evidence from the investigations of Notomastus latericeus Sars here described. The adult is found in mud or muddy sand. Experiments showed that larvae of this species if provided with mud or sand generally metamorphose several days before those kept in clean glass vessels or with clean shell gravel. Mud perhaps induces slightly more rapid settling than sand. After metamorphosis the growth and health of the young worms is generally much better in mud or sand than in gravel or clean glass vessels.

1. Samples of herring from the Clyde sea-area were obtained weekly from the time of hatching in March until metamorphosis in June.

2. The rate of growth was regular, about 3 mm. in length per week; the development was similar to that described from elsewhere.

3. The herring which hatched off the south-west of Arran gradually moved northwards into the mouth of Loch Fyne and remained there until metamorphosis.

4. The proportion feeding was usually small. The food consisted mainly of copepods, both young stages and adults. The size of the food organisms eaten depended roughly on the size of the herring

The sodium, potassium, calcium, iron and copper have been determined in sixteen marine gastropods, and the results are briefly discussed. A noteworthy finding is the large amount of potassium, calcium and (or) magnesium which may be present in these animals. Lacuna vincta for example may contain over I-I % of potassium, Archidoris britannica 1-58 % of magnesium per 100 g. of live weight

The body of Archidoris britannica contains very high concentrations of calcium and magnesium which appear to be combined mostly with CO3 and fluoride. The bulk of these materials are in solid deposits throughout the submucous tissue. Sodium chloride and potassium phosphate account for most of the residual mineral matter.

The mucus secreted by the body has an inorganic composition resembling sea water.

The visceral mass contains only one-tenth as much calcium and magnesium as the body. The predominating bases are potassium and sodium and the acid radicles are essentially chlorides and phosphates.

A study has been made of the seasonal and other variations in the contents of fat, water and total solids (other than fat) of the flesh of herring. The herring studied were mainly from Scottish and Shetland waters.

Various races of herring, differing anatomically and with different spawning seasons, are considered separately.For each, the observed changes in chemical composition are considered in relation to the season of the year and the feeding and spawning cycles of the fish.

During May and June there is a rapid rise in the fat content of herring (demonstrated for some races and inferred for the rest). This is correlated with a period of intensive feeding. After the attainment of maximal values in July there is a fall to minimal values in April. The rapidity of the fall depends on the spawning season, a relatively high fat content being maintained until spawning takes place. During spawning there is a rapid fall in the fat content, due, in part at least, to cessation of feeding.

The importance of killing contractile animals in an expanded condition cannot be over-estimated. A glance at the immense confusion and uncertainty which prevails in several branches of tropical marine invertebrates, and in particular the Coelenterata, will give a clear picture of the value of good preservation. Killing contractile animals in an expanded condition has always offered considerable difficulty. Several methods have been recommended for different animals, but it is often very difficult to choose the appropriate one, since animals belonging to one and the same group may behave quite differently towards any method. The writer, during his work for the last three years at the Marine Biological Station of the University of Cairo at Ghardaqa in the Red Sea, has taken great pains to preserve a variety of marine invertebrates as fully expanded as possible. Some of the successful results and the methods used are therefore given here.

The commonest method for the present purpose is the use of narcotics. The most familiar of these are menthol, chloral hydrate, alcohol, magnesium sulphate and cocaine. Owing to the difficulty in obtaining cocaine it cannot be freely used for general purposes. Menthol enjoys a great reputation for narcotization which, in fact, it does not quite deserve. Although in some few cases it gave good results, yet in the majority it was quite unsatisfactory, as delicate animals begin to macerate before they are properly narcotized. It is generally applied in the crystal form and sprinkled on die surface of the water. Apparently its low solubility is responsible for a great many of its failures.

1. A method, due to Poole & Atkins, is described for computing the total available energy at any depth in the sea, in joules or g.-cal.

2. The oxygen production of pure cultures of the diatom Coscinodiscus excentricus Ehr. was measured by the Winkler method after exposure of the diatoms in bottles at known depths in the sea. 3. The results of simultaneous measurements of oxygen production and of energy are given for 6 days in July and August 1933 and 1934.

4. Factors, other than light, that might affect the rate of oxygen production in the experiments are discussed and shown to be negligible. It is assumed that diatoms can use energy for photosynthesis equally well in all parts of the visible spectrum.

5. When the energy flux during the exposures is less than 75 joules or i-8 g.-cal. per cm.2 per hr., the oxygen production is directly proportional to the energy. The utilization of the available energy then amounts to about 7%.

Comparison of the methods of adhesion and locomotion of the typical members of the four classes of the Eleutherozoa reveals a similarity of the adhesive mechanism in the Asteroidea, Echinoidea and Holothuroidea in that adhesion is due in part to suction and in part to the secretion of mucus. The ophiuroid, on the other hand, has tube feet which, because of their lack of a well-defined sucker, must adhere merely by their intrinsic stickiness. The ability to make use of suction results from the possession of a sucker so fashioned that the median part of the disk may be withdrawn from the surface of contact, with the resultant production of a vacuum. The sucker of the asteroid, echinoid or holothurian tube foot is well adapted for this purpose. An essential feature of such a disk is the presence of an arborescent system of connective tissue fibres extending from the basal plate to the outer limit of the ectoderm. By means of this system, the pull initiated by contraction of the longitudinal musculature of the podium is transmitted to the ectoderm of the sucking disk, the central part of which is thereby lifted up. Where suction plays no part in adhesion, as in the Ophiuroidea, the arborescent system of fibres is lacking.

1. Dead marine diatom plankton was found to undergo rapid oxidation and decomposition when added to fresh sea water. This was measured by oxygen consumption, nitrogen liberation, phosphate regeneration and bacterial multiplication.

2. Living diatoms added to sea water and placed in the dark continued to absorb oxygen; they were rather resistant to bacterial attack.

3. Diatom-rich marine plankton also absorbed oxygen, while the phosphorus was gradually regenerated. The bacteria did not increase in numbers in correspondence with the oxidation of the fresh diatom material.

4. When sea water in which photosynthesis was allowed to proceed for varying periods of time was placed in the dark, rapid oxidation of the freshly synthesized material took place, as indicated by oxygen consumption and phosphate liberation. Although there was a greater number of bacteria in the water in which photosynthesis took place, the oxidation of the fresh diatom material was not accompanied by any large increase in bacteria; in fact a decrease in numbers was frequently observed.

Four ordinary and two special meetings of the Council have been held during the year in the Rooms of the Royal Society, London. The average attendance at the ordinary meetings was sixteen. The thanks of the Association are due to the President and Council of the Royal Society for allowing their rooms to be used. A Committee of the Council, consisting of Prof. E. W. MacBride, F.R.S., and eight other members, visited and inspected the Plymouth Laboratory on April 18.

The Council has to record with deep regret the death of Mr Howard Dunn, an Associate Member. As Chairman of the Cornwall Sea Fisheries Committee, Mr Dunn had been in close personal touch with the staff and work of the Plymouth Laboratory.

Retirement of Dr E. J. Allen.

During the year the Council learnt with the greatest sorrow that Dr E. J. Allen had decided to retire from his post as Secretary of the Association and Director of the Plymouth Laboratory. For forty-two years Dr Allen has given unremitting service to the Association, and under his wise guidance the Laboratory has risen from small beginnings to the premier position which it holds to-day. The progress which has been made and the high standard of original work which has been produced are due in a very large measure to his devotion to the interests of the Laboratory and to his gift for inspiring others with his own enthusiasm. The Council is gratified to learn that his eminent services to science have been recognized by the award of the Darwin Medal of the Royal Society.