The genus Edwardsia is one known to most zoologists as an example of a primitive eight-rayed Zoantharian from which (or from a form resembling which) the higher forms are derived. It is only comparatively recently, however, that our knowledge of Edwardsias has become at all extensive, and even now it is incomplete; but it is desirable to produce a revision of the British forms since no adequate account of these exists.

The following paper has been prepared in the hope that it will be of assistance to anyone desirous of carrying out experiments on Heredity with Gammarus chevreuxi. This Amphipod has been the subject of study at the Plymouth Laboratory since 1912, and the following notes are chiefly concerned with rearing and breeding it under Laboratory conditions.

Details of the work will be found in the papers mentioned in the bibliography on page 54.

Thysanoessa raschii is a regular inhabitant of the Firth of Clyde. Adults are found throughout this area, generally in waters not less than 40 fms. deep. Those of large size, 23–25 mm., are apparently consistently found from year to year in Loch Striven in large numbers from October to January within 10 fms. from the bottom in waters of 40 fms. depth. Throughout the rest of the year they occur in small numbers in the tow-nets, and are seldom found at all during the summer months. On one occasion, however, February, 1926, several hundreds were fished in addition to large numbers of Meganyctiphanes norvegica at 40–60 fms. in the Cumbrae Deep.

In 1925 observations were carried out on two consecutive nights, June 17–18th and 18–19th, to study the diurnal changes occurring in the vertical distribution of certain marine plankton animals. Serial hauls were made with the stramin ring-trawl in the manner described in a previous publication (1). The series were so timed that they were made approximately in daylight, dusk, darkness, dawn and daylight on the two days in question. The actual details of the collecting, together with the fishing depths shown by the Admiralty depth recorder, are to be found in a previous paper on the behaviour of young fishes on the same occasion (2).

In the course of the researches on the vertical distribution of plankton it became evident that a net was needed for sampling the water-layers very close to the sea bottom. While the net had to be efficient in capturing the plankton animals present in those layers, it was necessary that the catches should not be vitiated by the presence of bottom-living organisms which had been stirred up from the sea floor by the net itself.

Further study of the larval crabs of the Plymouth district has resulted in the elucidation of many more life-histories. Amongst these perhaps some of the most interesting are Ebalia and Pinnotheres. These genera, placed by systematists in widely different groups, resemble one another closely in many details in their larval stages and are here purposely described together in order that a comparison may be made.

The Cirripede Anelasma squalicola (Lovén) is parasitic on the smooth dogfish, Etmopterus spinax (Linnæus). These fish, which are caught a depth of about 150–180 fathoms, were brought to the University of Liverpool as material for a chemical investigation by Professor Heilbronn and his colleagues. On finding that some of the fish were thus parasitised, Professor J. Johnstone and myself made a study of the general morphology of Anelasma (3).

1. The larva of a Terebellid which is very common in plankton from the Plymouth district during spring has been reared and proved to be the young of Loimia medusa Sav. This larva is characterised by its very large gelatinous tube.

2. The development of the external structures is described from a stage in which the first tentacle was just appearing to a juvenile stage in which all the main characters of the adult had been assumed.

3. The building of the first sandy tube on the bottom is described.

4. The development of the bristles and uncini are dealt with in some detail and a comparison made with the corresponding development in Nicolea zostericola. Evidence of the suppression of a pair of larval bristle-bundles in Loimia is indicated.

5. Previous records of Loimia larvse are discussed.

6. McIntosh's separation of our British Loimia to a new species, L. montagui, is shown to be probably unjustified.

1. Regeneration from different levels in the polychæt worm Chætopterus variopedatus has been studied.

2. Regeneration can occur posteriorly from any segment, but anteriorly only from segment XIV forwards.

3. Where regeneration occurs at all, given sufficient time, it will be complete, i.e. the original segments occupy in the new worm the relative position they originally occupied in the old worm.

There has existed in the past, and still does exist, considerable confusion both in the question of a satisfactory basis for the classification of ascidians and that of the validity of many species.

The principal orders and families are fairly stereotyped, and confusion and divergent opinion is mainly confined to the internal classification of the various families. These differences have a twofold origin, in that classifications have been constructed by various authors on three distinct bases, and that it is very difficult to distinguish between structures which are similar through relationship and those which are similar through convergent or parallel development. Further difficulty arises from the fact that authors describing a new species with a view to fitting it into one particular classification, have often given insufficient details for its accurate inclusion in another scheme. There is also divergent opinion as to the correct nomenclature that should be employed, but with that this paper is not concerned.

The nomenclature followed is that used by Hartmeyer (9), in which account will be found identificattion keys and complete lists of the synonymous species, only the commoner of which are given below. That his conclusions in this respect are open to question has already been pointed out (see Journ. Mar. Biol. Assoc., Vol. XV, p. 159).

For a description with figure of a species the reference number is placed after the name.

1. Observations made subsequent to December, 1925, confirm the conclusion that the nitrates in the water of the English Channel, twenty-two miles south-west of Plymouth, are almost entirely utilised by phytoplankton in the summer, and are reformed in early autumn at a greater rate than they are utilised.

2. Movements of the water masses are shown to affect the quantity of nutrient salts available for phytoplankton in the waters immediately north of Ushant.

3. The effect of land drainage on the quantity of nitrate in the sea is not apparent beyond a few miles to seaward from Plymouth Sound, being masked by the nitrate which is regenerated from dead marine organisms.

4. The nitrate in the river and estuarine waters entering Plymouth Sound is nearly all utilised by plants in the rivers and estuaries themselves before reaching the open sea during summer.

1. A comparison of the strength of the wind, Beaufort Scale, and of its direction during the periods when the vernal diatom outburst caused phosphate depletion of the surface water, has failed to indicate that there is any connection between either strength or direction and the date of the outburst. The spring sunshine still appears to be the important factor at El.

2. The sequence of the years studied as regards the main spring diatom outburst deduced from phosphate depletion at Station El is as follows: 1924, early March; 1926, late March to early April; 1925, early April; 1923, early May.

In the whiting, no significant changes occur in the composition of the muscle substance, either throughout the year, or with increasing age, or during ripening of the gonads.

The amount of fat in the liver is very low in immature fishes, increasing greatly with age, and reaching its maximum just after the commencement of the ripening of the gonads. It then falls off, reaching its lowest value amongst mature fishes in the “Spent” stages. Males are richer in liver fat than females.

Immature fish have a decidedly higher protein content in the liver than have mature fish.

1. Under the conditions of the tests cotton and hemp nets became rotten in Aquarium tank water in two months or less in summer, in 4½–5½ months in winter.

2. A mixed copper soap, containing oleate, stearate, and palmitate, is as good, probably rather better, than is copper oleate as a net preservative.

3. “Cuprinol,” a petroleum acid copper soap, is better than the fatty acid soaps, both in fresh and in salt water. It is more than three times as expensive, however.

Towards the end of the year 1924, the present writer commenced a statistical study of random samples from commercial landings of herrings at Plymouth, in order to obtain information on the two following questions:—

(a) Upon what year-class or year-classes of herring was the season's fishery of 1924–25 concentrated?

(b) Did the fishes landed throughout that season appear to conform to a single morphological type?

The published observations of other workers, on samples of herrings taken from the area under consideration, whether they relate to the study of such morphological characters as the number of vertebræ and keeled scales, or are chiefly concerned with the examination of the growth of the fishes as indicated by their scales, demonstrate very clearly that the eastern, central and western sectors of the area are visited by herrings which differ in character. It will be convenient to summarise the opinions of these workers under the headings of the statistical regions in which the samples were taken. The reader is referred to the chart on page 269, which shows the geographical extent of the regions dealt with.

Although locally caught drift herrings may be landed at Plymouth from the end of September onwards until the beginning of March, the fishery only assumes economic importance during the months of December and January, when a large number of visiting drifters from both Cornwall and East Anglia are making daily fishing trips, using Plymouth as their temporary base.

Comparatively little has been published concerning the habitat and growth of young herrings in the English Channel, especially during the first year of their life. On May 26th, 1927, the first of a series of hauls with a small-meshed Saltash tuck seine (vide Davis, 1, p. 70, for a description of this type of net) was made in the River Tamar and a fine haul of young clupeoids obtained, which included the young of the herring, sprat and pilchard. Since then, regular samples have been taken from the rivers Tamar, Tavy and Lynher, and sufficient numbers of young herrings collected on each occasion to give a reasonable indication of the length-distribution prevailing. Sampling is still in progress and will be continued until one year's observation has been completed, but sufficient data are now to hand to merit an initial report. The localities from which the samples were obtained are indicated in the accompanying chart.

Photosynthesis in the open sea is due mainly to two groups of organisms, the diatoms and the dinoflagellates. In British seas the diatoms are so much more numerous that the chemical changes which are due to photosynthetic activity can be almost entirely ascribed to their influence. Recent work on these chemical changes has shown that they do not extend deeper than about 30 metres. Of the external limiting factors light is among the most important and the depth to which photosynthesis can go on must, of course, depend on the light intensity. In the study of the phytoplankton under natural conditions the results are complicated by the interaction of many other factors such as temperature, viscosity, or lack of food salts, so that it is difficult to come to definite conclusions on the effect of light alone.