1. Young angler-fishes have been kept alive and in health for periods varying from a few weeks to eleven months. They were sometimes hand-fed on dead fishes and sometimes allowed to catch living prey. They grew at an average rate of about eight and a half inches per annum. All had strongly marked individual characters.

2. With pelvic and pectoral fins a slight hollow is made in the sand into which the angler settles itself. Its upper surface is now flush with the ground, and the colour and colour mottlings are closely matched to the surroundings. The bordering tags of skin break up the outline.

3. Breathing movements occur at relatively long intervals. The expiratory currents are discharged in the axils between the pectoral fins and the trunk, and are deflected vertically upwards.

By the use of a “conditioned response” technique it has been shown that teleostean fishes respond “purposively” to an increase in temperature of the water surrounding them of between 0-03° C. and 0-10° C. It is probable that the former figure is true for all the species investigated, but it has only been practicable to establish it with certainty in a few sedentary forms

1. This paper deals with certain experiments on training fish (Ctenolabrus rupestris L.) to swim round obstructions to reach food, for the purpose of investigating how their learned response was developed. The whole question as to how learning which involves “problem-solving” is rightly to be interpreted and harmonized with our knowledge of conditioned responses, presents difficulties which have not yet been adequately faced.

2. A description is given of the results of experiments carried out on eleven fish. The fish had to learn a detour route either into a pot or round glass plates. Attention may be drawn to the great diversity in the behaviour of individual fish, both in their reactions to the obstruction at different stages of training, and in the method by which they succeeded in passing it. Some individuals are evidently more capable of profiting by experience than others.

1. The diameters of samples of Rhizosolenia stylijormis taken in the S. W. North Sea between 1932 and 1934 revealed the presence of large and small populations. The largest diatoms were found in 1933, in which year, or late in 1932, it was thought that auxospore formation might have taken place.

2. The large and small groups mentioned in (1) gave indications of a continuous diminution of size judging by an inspection of their modes. Notwithstanding this there appears to have been some selection of the larger cells, as the whole samples tended to increase in size with a rise of temperature.

3. The correlation coefficient between the temperature at 20m. and the mean diameters was 0-59. That for salinity in the same circumstances was 0-59. The inverse correlation with salinity is thought to be due to the topography of the area.

By examination of samples of Purpura lapillus from the whole of their European range, it appears that the species can exhibit quite as wide variation within a relatively small region such as that studied in the Dorset-Devon-Cornwall area, as it can over its whole geographic range. Population samples were taken from seventy-six localities, mostly in the south-west of England, and covering a wide range of environmental conditions, and the variations in these shells were studied in relation to two primary environmental factors, degree of exposure to wave-action and diet.

1. An air turbine ultracentrifuge suitable for biological work and capable of developing a centrifugal force from 10,000 to 500,000 times gravity has been described. Advantages of the ultracentrifuge are: (1) The temperature does not vary in the centrifuge chamber over 2 or 3 degrees from that of the atmosphere; this is not sufficient to be an important factor in general biological work. (2) The cost of constructing the apparatus is very low in comparison with that of other high speed centrifuges.

2. A modification of the air turbine ultracentrifuge in which the turbine rotor drives a second rotor, in this case the centrifuge rotor which spins in a vacuum, has been described. Here the centrifuge chamber is thermally insulated which is an important item in preventing troublesome convection currents from arising in the centrifuged material where such special problems as the rate of molecular sedimentation are being observed. Forces in excess of one million times gravity can easily be obtained by such an apparatus.

During 1934–5 I collected in Plymouth Sound and neighbouring waters seven species of the genus Corophium of which two were undescribed. I also collected one other species, and had sent to me two other species (one new) from other localities in South England. A list of these ten species, with the single other species known from Britain, is given in Appendix II, and their British distribution summarized.

In the course of identifying them I examined 23 of the 32 species of Corophium, and saw all the literature to which I could find references.

Several small anemones resembling Metridium dianthus were collected from the River Roach and sent to me in the summer of 1934. A careful examination proved them to be Diadumene cincta which was first recorded from Plymouth. T. A. Stephenson (1, 1925, p. 880) described both an orange and a fawn variety of this species, the former from the Breakwater and the latter from the Pier, Plymouth. The Roach anemone agrees with the Plymouth one in all its more important habits and its external and internal characters. It would appear that the specimens of D. cincta from the New England Creek, Essex, recorded by T. A. Stephenson (2, 1935) since this account was first written, may have been derived from this river.

The anemones were dredged in abundance from the River Roach attached to living and dead shells of Ostrea and Mytilus and to Alcyonidium and Halichondria. All (about thirty) which I have seen were small, the diameter of the base averaging 0.6 cm. and the disc 1.5 cm. They were orange, but some were pale while others were more deeply coloured. No fawn ones have as yet been found in this locality.

The scapus wall is thin, translucent with a bluish caste and with the mesenterial insertions showing through. The cinclides are evident as distinct dull purple-grey spots, each with a central depression clearly visible under a hand lens. The tentacles are the same colour but paler than the scapus. They are usually uniformly coloured but in some specimens there are two faint bluish lines running along their upper surface and, in one individual, there was a pair of short dashes at their bases instead of these lines.

The earliest detailed account of the nature of the sea bottom near Plymouth is that of Allen (1899), wherein analyses of the soils on the 30 fm. line are coupled with lists of the animals collected by trawl and dredge. Ford (1923) described a number of soils in shallower water, and gave a quantitative list of the bottom fauna, collected with a grab which covered an area of 0·1 sq. m. Smith (1932) described in great detail the soils of the area of shell-gravel which surrounds the Eddystone Lighthouse. By none of these workers, however, was special attention paid to the smaller burrowing Crustacea, which are often overlooked unless they are made the special object of collecting. Some species, e.g. of Bathyporeia and Ampelisca, may be very common, and certainly play an important part in the ecology of the sea-bottom. See Steven (1930) and Hunt (1925).

This list contains 2 species of Tanaidacea, 6 of Isopoda and 28 of Amphipoda. These were all collected by myself in 1934–5, with the exception of 3 species of Amphipoda, which have not been entered in the Plymouth list although accounts of their capture at Plymouth have been published. These are Eusirus longipes Boeck, recorded by Hunt (1924); Gammarellus angulosus (Fabr.), by Kitching, Macan and Gilson (1934); and Gammarus zaddachi Sexton, by Serventy (1935).

The list is drawn up in the systematic order adopted in Plymouth Marine Fauna (1931), with a reference to a good illustration of each species. The dates and circumstances of capture are stated, and when a species has already been recorded from off the coasts of Devon and Cornwall by Norman and Scott (1906) a note to that effect has been made. The distribution is not stated, since recent accounts of the distribution of every species are available in the following works:

Tanaidacea and Isopoda: Nierstrasz and Stekhoven, 1930 (except for Synisoma acuminatana, q.v.).

Amphipoda: Chevreux and Fage (1925) or Stephensen (1929).

All the Amphipod species in this list are included in one or other of these publications, and almost all in both.

Every species has been referred to a specialist for identification. Tanaidacea and Eurydice truncata and Gnathia oxyurœa to J. H. Schuurmans Stekhoven of Utrecht; the other Isopoda to Prof. W. M. Tattersall of Cardiff; the Amphipoda to Dr. K. Stephensen of Copenhagen, excepting Gammarus zaddachi Sexton, which Mrs. Sexton herself has named.

Descriptions of the hydroid Zanclea implexa (Alder) in British waters have been given by the following authors, Alder (1857, as Tubularia implexa and Coryne pelagica), Allman (1859, as Coryne Briareus), Strethill Wright (1859) and Alder (1862 as Coryne implexa), Allman (1864 as Zanclea implexa and 1872 as Gemmaria implexa) and Hincks (1872, as Zanclea (Gemmaria) implexa). All these descriptions have been based upon full grown colonies in which the hydranths had a perisarc on the hydrocaulus.

During the summer of 1935 Captain Nicholson of Saltash kindly put his motor-boat at my disposal and took me for seven full-day collecting trips on the estuaries of the Tamar and its confluents, the Tavy and Lynher. I also made some collections from land in the estuaries of the Plym and Exe (S. Devon), Taw (N. Devon), Camel (N. Cornwall), and Towy (S. Wales).

All collecting was done intertidally or in shallow water and was practically confined to the brackish-water reaches. No gear was used except a hand-net of stramin, and a zinc sieve of 1-mm. mesh. More attention was paid to the Crustacean orders Tanaidacea, Isopoda, and Amphipoda than to the rest of the fauna, observations on which were only occasionally made.

In the last number of this Journal (Russell, 1936) I described under the name Eucheilota hartlaubi the adult and various stages of a medusa that is fairly common in the Plymouth plankton but had up till then remained undescribed. This medusa was identified with an unnamed medusa which Hartlaub had figured as having been reared from the hydroid Lovénella clausa Lovén.

On March 10th, 1936, some Lovénella clausa kept in this laboratory by Mr. W. J. Rees liberated medusæ. Mr. Rees kindly handed these over to me so that I could follow the early development. When first liberated the medusa was conically bell-shaped (Fig. 1) and there were scattered nematocysts on the exumbrella. There were two fully developed opposite perradialtentacles, and two non-tentacular perradial bulbs. Rudiments of spiral cirri were developing on either side of the tentacular bulbs. There were four interradial marginal cirri each of which was situated on the umbrella margin about midway between the tentacular and nontentacular bulbs.On the tentacle sides of each of these marginal cirri was a marginal vesicle with a single concretion. The medusa was 0.75 mm. high by 0.75 mm. broad. The colour of the tentacular and non-tentacular bulbs and the stomach was pale straw. By the next day the umbrella had assumed amore oval bell-shape and the colour of the bulbs and stomach was now a bright orange-yellow. OnMarch 12th the medusa was now 0.9 mm. high and the rudiments of cirri were developing on one side of each non-tentacular bulb (Fig. 2).

While examining a bowl of rock dredgings from the Mewstone Grounds near Plymouth, on 10th December, 1926, my attention was attracted by a handsome Phyllodocid worm which had evidently crawled out of a crevice in the broken rocks. On closer investigation the worm proved to be of an unfamiliar species and, of much greater interest, to possess a small secondary tail arising ventrally rather more than two-thirds of the way down the body (Fig. 1). Scale drawings, made at the time from the living animal, have recently been carefully checked by examination of the preserved specimen; only a few slight alterations have been found necessary.

Determinations of organic phosphorus (so called) have been made in waters from off Plymouth. The amount varies little with the time of year and averages 0·44 mg. -atom per cubic metre. This is of the same order as determinations in other parts of the North Atlantic. About one-half of this “organic phosphorus” is considered really to be arsenite.

The writer has recently reared a species of hydroid at Plymouth, which, in the vegetative state, might easily be confused with Slauridium productum Wright, 1858. The original creeping stolon from which the colony developed was found on a piece of dead Eunicella verrucosa (Pallas) dredged by the S.S.Salpa near Stoke Point on March 9th, 1936.

When isolated in a finger-bowl with “outside” sea water the stolon bore no polyps and showed no sign of activity, but three weeks later a single polyp had developed (Fig. 3). From its close resemblance to the figures given by Hartlaub (1895) for S. productum, it was at first assumed to be this species and was carefully watched and fed in the hope of rearing the medusæ from it. After a period of time, however, when the colony had increased considerably in size, styloid gonophores were developed.

The type of growth of the fully grown colony is shown in Figures 1 and 2. The stems are elongated and slender, bearing polyps at intervals. Polyps are borne at the summit and also on branches of the main stems. These branches usually arise from one side only of the main stems and it is probable that under natural conditions in the sea these main stems are really stolons. It is also likely that in nature the intervals between the polyps are fairly short. The whole colony has a faint yellow-brown colour which becomes reddish-brown in the polyps and the upper part of the hydrocaulus.

A troublesome problem arises in connexion with the tracing of Trematode life histories; namely how to obtain the intermediate and final hosts free from Helminth infections. It was discovered—fortunately early— during the study of the parasites of Peringia ulvœ Pennant 1777, that all the species of certain groups of cercariæ, and also related species from other molluscan hosts, encyst most readily in the same species of fish or crab. It is therefore not surprising if the mature trematodes are also to be found in the same host. It is obvious that the greatest confusion can arise from these facts. To add to the difficulty it is often impossible to distinguish between the worms within the cyst, and therefore the dissecting out of cysts for feeding purposes is impracticable.

By far the most satisfactory results are obtained by rearing the hosts in the Laboratory, but unfortunately with marine organisms this is often impossible.

The Black-headed Gull was selected as the final host in a series of experiments, approximately 40 Helminth parasites having been recovered from this bird in Europe. Attempts were made to rear the bird in captivity.

Two dozen eggs were first placed under various hens, but all those were lost owing to the great fragility of the shells. The birds invariably smashed the eggs in turning them. An incubator was then tried but a large series of failures also occurred before the discovery of the correct temperature. Subsequently half the birds died on account of wrong treatment after hatching.

In continuation of the three previous reports on the seasonal abundance of the pelagic young of teleostean fishes (Russell, 1930, 1935 and 1936) the corresponding data for the year 1936 can now be given. These are published in the same form as in the previous reports to which reference should be made. The dates on which the collections were taken are given in Table I and the monthly average catches for the young fish in Table II. No observations were available between October 12th and December 16th, but this does not materially affect comparison with other years because normally the young fish present at that time of year are very few in number

1. Aporrhais pes-pelecani occurs on muddy gravel at moderate depths and is specialized for burrowing in this.

2. The mode of burrowing is described and also the formation of mucuslined inhalent and exhalent openings by the proboscis.

3. There is a powerful respiratory current through the mantle cavity which also possesses three sets of ciliary currents for disposing of sediment carried in with this.

4. The animal is a specialized detritus feeder selecting only material of plant origin. The radula consists of one central and three lateral teeth on each side, an indication that it is used for seizing as opposed to scraping, not that the animal is carnivorous.

5. The stomach possesses a well-developed ciliary sorting mechanism. The large crystalline style and gastric shield indicate that the animal is herbivorous, but there is no cellulase.

A number of naturalists have expressed their belief that the movements of the adult herring (Clupea harengus L.) at certain seasons are governed by the relative abundance or scarcity of their food or other organisms in the plankton.