bluuebunny/crossref_metadata_2025 huggingface dataset:
Vitamin A and carotenoids in certain invertebrates: V. Mollusca: Cephalopoda
Authors: Fisher L. R. , Kon S. K. , Thompson S. Y.
Published: May 2009

In our previous paper (Fisher, Kon & Thompson, 1956) on Mollusca we pointed out that the Cephalopoda were so different from the other classes in vitamin A and carotenoid relationships that they would be more satisfactorily considered separately. We have so far analysed ten species of cephalopods and found vitamin A in all of them. The studies of previous investigators of vitamin A in these molluscs were confined to its function in the visual cycle and to its contribution to the vitamin A reserves of sperm whales feeding on cephalopods. The carotenoids of cephalopods have been given even less attention than vitamin A.
Studies on the biology of limpets: I. The late J. H. Orton's work on Patella
Authors: Southward A. J. , Dodd J. M.
Published: May 2009

At the time of his death in 1953 Orton had almost completed an extensive study of the biology of the three British species of Patella. Although certain aspects of the investigation were dealt with by collaborators and have already been published (Crewe, 1947 on parasites; Goodwin, 1950 on pigments; Jones, 1948 on ecology) most of the breeding and spawning data have been neither analysed nor published. With the knowledge that Orton's records contained the most complete information on breeding yet compiled for a littoral animal, and that these records had considerable bearing on the question of speciation in Patella, we have attempted to analyse and present those which are most complete.
The accumulation of radioactive iodine by Amphioxus
Authors: Thomas I. M.
Published: May 2009

The endostyle of Amphioxus has for a long time been regarded as homologous with the subpharyngeal gland of the cyclostome ammocoete larva. This view was promulgated by Müller (1873) and by Dohrn (1886), and has been supported by many workers, for example Leach (1944). The metamorphosis of portions of the subpharyngeal gland to the thyroid gland of the adult lamprey was followed by Marine (1913), and uptake of radioactive iodine by certain cell elements of the subpharyngeal gland was demonstrated by Gorbman & Creaser (1942). At the same time the latter workers failed to establish the presence of iodine in the endostyle of Amphioxus by autoradio-graphic techniques. Gorbman (1941), however, showed that the ascidian Perophora annectans could accumulate radioactive iodine in its pharyngeal stolon but not in its endostyle. The part of the pharyngeal stolon involved is derived from the endostylar region of the pharynx. Recently, Sembrat (1953) has shown that endostyles of Amphioxus implanted into larval axolotls accelerated their metamorphosis, and concludes from this that the organs contain an ‘active substance (or substances) which may evoke amphibian metamorphosis similarly to the active hormone of the thyroid gland. It is probable that the substance is not identical with thyroxin which may be inferred from the fact that the endostyle’ of Branchiostoma does not accumulate radioactive iodine (Gorbman & Creaser, 1942) as well as from its different and tolerably little efficacious influence on the amphibian metamorphosis as compared with typical metamorphic symptoms induced by the thyroid gland.’ The work about to be described has demonstrated the presence of iodine in the endostyle, and suggests, further, that it is present in the form of a ‘thyroid hormone-like’ substance, thereby supporting Sembrat's general conclusion.
Fluctuations in the distribution and abundance of intertidal barnacles
Authors: Southward A. J. , Crisp D. J.
Published: May 2009

It is well known that towards the limits of an animal's geographical range both its abundance and exact boundaries may fluctuate from time to time. These fluctuations can sometimes be correlated with environmental changes, and thus may help to assess the relative importance of the factors that control distribution. For example the distribution of the common intertidal barnaclesChthamalus stellatus(Poli) andBalanus balanoides(Linnaeus) underwent changes which were attributed to a general rise in temperature over several years (Southward & Crisp, 1954a). The abundance of these barnacles has fluctuated further since 1951–52, and we are now able to analyse more closely the relation between the population changes and environmental variations.
The Early Stages of Nephrops norvegicus, from the Northumberland Plankton, together with a note on the post-larval development of Homarus vulgaris
Authors: Jorgensen Olga M.
Published: May 2009

Although adult Norway lobsters are extremely common on the southern part of the Northumberland coast, there were no records of the taking of larvæ of the species in this part of the North Sea until the Plankton Investigation now being carried out at Cullercoats (1) was commenced.

During the period 1921–23 a few specimens were taken from time to time in the ordinary plankton hauls, but the best catches of Nephrops larvæ were obtained from the young fish trawl used at a number of stations in 1922 arid 1923. It is, therefore, chiefly on the material from the last two years' samples that the following observations are based.

All three of the larval stages have been obtained, together with a single post-larva, but the majority of our specimens are second and third stage larvæ.
A New Type of Luminescence in Fishes
Authors: Hickling C. F.
Published: May 2009

A luminous organ of a hitherto undescribed type has been found in a Macrurid fish. This organ is described in the present paper. It consists essentially of an epithelium for the secretion of luminous substance, which has been thrown into long folds and wholly invaginated to form a gland. This gland is bound in connective tissue and has a compact appearance, and is furnished with supporting tissue internally. The duct is a flat and wide passage, continuous with the gland, which opens to the exterior about the anus in such a way as to surround the lower part of the rectum. The gland lies in the thickness of the body-wall forward of the rectum and between and behind the pelvic fins.

The nature of the secretion is discussed and some experiments described. The luminescence appears to be due not to bacteria living as guests within the tissues of the fish, as has been shown for other species, but is essentially due to the well-known reaction wherein a substance luciferin is burnt to oxyluciferin in presence of the ferment luciferase, with emission of cold light.
On the Occurrence of Onchidella celtica (Cuvier) on the Cornish Coast
Authors: Russell F. S.
Published: May 2009

Onchidella celtica (Cuvier) is the only representative of its genus found on our shores. Included in the Sub-order Stylommatophora of the Pulmonates, it is believed to be a land mollusc that has reverted to a marine habitat. It is quite devoid of a shell and closely allied to the land slugs.
Rays and Skates (Raiœ) No. 1.—Egg-Capsules and Young
Authors: Clark Robert S.
Published: May 2009

The family Raiidæ belongs to the division Batoidei of the sub-order Hypotremata, and is represented by the principal genera Raia, Psammobatis, and Sympterygia (Regan, 1906). The genus Raia (an altered spelling of Raja) was instituted by Linnæus, after Artedi, for the type Raja batis in the Systema Naturæ, Ed. X, Vol. I, 1758. The species are numerous and mostly of northern distribution.
On the Manufacture of Drift Bottles
Authors: Nelson E. W.
Published: May 2009

In the spring of 1920 the Ministry of Agriculture and Fisheries approached the Marine Biological Association of the United Kingdom with a view to the Association undertaking the manufacture of a large number of “Drift Bottles,” to be used in an extensive research into the resultant movements of the waters of the North Sea.
The Respirable Organic Matter of Sea Water
Authors: Atkins W. R. G.
Published: May 2009

1. On storing, sea water suffers a decrease in pH value. The amount of change varies from that produced by adding 1·0 c.c. of N/100 acid to 100 c.c. of sea water, up to that due to adding about 2·5–3·0 c.c. The decrease is due to the production of carbonic acid by organisms.

2. The change corresponding to 1·0 c.c. of acid, as above, is equivalent to that produced by the complete oxidation of 3 milligrams per litre of a hexose sugar, which requires 3·2 mgrms. per litre of oxygen. This is the minimum value, from 8·0–9·6 mgrms. corresponds to the higher values of acid. Figures for oxygen consumption by estuarine waters, which are available for an approximate comparison, show that 1·5 mgrms. of oxygen is not often exceeded in estimations by means of alkaline permanganate. The highest of this series is 5·6 mgrms. It is suggested that the different results given by the two methods are due to the fact that respiratory changes taking place in the water during storage set free much of the organically combined carbon before the oxidation by permanganate has been started. Determinations on freshly drawn filtered sea water give, according to Raben, 7·5 mgrms. of hexose or 8·0 mgrms. of oxygen consumed.

3. It is probable that the change in pH value on storing indicates the amount of plankton present, at any rate when sewerage contamination is negligible. It appears that water near the surface, at 20–25 metres and sometimes at the bottom, 70 metres, is particularly subject to change during storage. Four cases out of seven showed marked decreases in pH value at 20–25 metres, and two others exhibited the change to a less marked degree.

4. The total amount of carbon, reckoned as hexose, which is set free during storage by respiration in sea water at E1 is about twice that photosynthesised between July and December, taking for this the minimum value 3 mgrms. per litre, namely a total of 6 mgrms. per litre. Considering the column of water from bottom to surface, this is equivalent to about 500,000 kilograms per square kilometre in the English Channel off Plymouth.
The Hydrogen Ion Concentration of the Cells of some Marine Algæ
Authors: Atkins W. R. G.
Published: May 2009

The measurements recorded for marine algæ of various groups show that the reaction of the sap is in most cases almost neutral, and in no case is the sap of the pronounced acid character met with in many land plants. This being so it follows that the enzymes concerned in the metabolism of these algæ must be quite different from those which effect corresponding changes in land plants, as may be seen on referring to the optimum pH values for various enzymes quoted in the writer's previous paper on the reaction of plant cells (1922).
The Influence upon Algal Cells of an Alteration in the Hydrogen Ion Concentration of Sea Water
Authors: Atkins W. R. G.
Published: May 2009

Sea water originally at pH8·2 became as alkaline as pH9·4 by the photosynthetic action of Ulva in removing carbonic acid. This degree of alkalinity did not prove injurious to Ulva, but exposure to it for two and a half hours at 27° C. sufficed to increase the permeability of the superficial cells of Ceramium rubrum irreversibly and fatally. Similar though less rapid changes brought about the death of numerous Vorticellæ epiphytic on Ceramium. The criteria for living cells were permeability to neutral red and impermeability to brom cresol purple. Dead cells do not retain neutral red specifically and are permeable to brom cresol purple.

It is suggested that the above facts have a bearing upon the distribution of these and similar algæ upon the shore.
The Vertical Distribution of Marine Macroplankton. VIII. Further Observations on the Diurnal Behaviour of the Pelagic Young of Teleostean Fishes in the Plymouth Area
Authors: Russell F. S.
Published: May 2009

Results are given of a further series of collections made with the stramin ring-trawl to determine the diurnal behaviour of post-larval stages of Teleostean fishes in the Plymouth area.

The catches were very satisfactory and showed that in no case, except for Clupeids and Gobies, was there any really marked movement of young fish towards the surface. This confirms previous observations.

It has been shown on this and previous occasions that Clupeids are many times more abundant in the catches at night than in the daytime, and any study of their seasonal or horizontal distribution would probably.have to be carried out at night.

For the remaining species, except perhaps Gobies and Callionymus, oblique hauls taken either at day or at night should give a fair picture of seasonal or horizontal distribution. More observations are, however, required.

The association of the whiting young with the medusa, Cyanea capillata, is discussed.
Observations on Patella Vulgata. Part II. Rate of Growth of Shell
Authors: Orton J.H.
Published: May 2009

Many common limpets Patella vulgata, settled and grew on the cement piles of a new wharf constructed at Plymouth. Each pile or part of this wharf provided experimental material for the determination of the maximum age of the limpets which grew thereon, as the dates of completion were known. It was found that at an age of about one year limpets grew to lengths of 26 to 35 mm. in 1912, and to at least 11 to 27 mm. in 1913 :and at an age of two years to at least 53 mm. in 1911-1913, and to 47-49 mm. in 1912-1914.

The shells were of the mid-tide-level type, and were low, broad, and rather thin. It is considered that such growth in length is unusual, and is correlated with the habitat and favourable climatic conditions. In the same situation in 1913 marked limpets grew from January 27 to September 2, respectively, 20 mm. (from 21 to 41) and 15 mm. (from 38 to 53), and showed arrest of growth in midsummer.

Other marked limpets showed arrest of growth in the winter period, and many at lengths of about 25 mm. an arrest of growth independent of any season of growth. Seasonal shell-growth is discussed briefly ; a postbreeding shell-growing period is general in spring and early summer, but it is not known whether a midsummer resting-period is general among individuals more than one year old. Ad hoc investigations are suggested in combination with work on sex and spawning.

A preliminary notice is given of investigations into the cause of variation in shell-height, wherein it is shown that shell-height is determined probably entirely by the degree of exposure of limpets to desiccation, in such a manner that the drier the habitat the higher the shell is. Limpets submerged at neap tides have a relatively uniformly low shell, those exposed at high-water neaps have a relatively high shell, which is higher in the drier than in the damper situations, apparently irrespective of exposure to wave-action.
On the Biology ofCalanus finmarchicus. Part VI. Oxygen Consumption in Relation to Environmental Conditions
Authors: Marshall S. M. , Nicholls A. G. , Orr A. P.
Published: May 2009

1. Experiments have been done to determine the oxygen utilisation by male, female and Stage V Calanus under different environmental conditions.

2. An initial fall in the respiration of adult Calanus was observed during the first few hours after capture. Stage V do not show this clearly. It is found more often in winter than in summer.

3. The lethal temperature varies from 24° C. in winter to 26° C. in summer. Stage V Calanus are more resistant to high temperatures than adults.

4. Respiration rises with increase of temperature from 0° C. to 20° C. The increase does not follow van't Hoff's law. The oxygen consumption of males and females is about the same, while that of Stage V is lower. Above 20° C. there is a harmful effect.

5. Within the limits studied (pH 7.4–pH 8.5) change in hydrogen-ion concentration has no effect on respiration.

6. Calanus are unaffected by an increase in the oxygen content of the water, but are sensitive to low oxygen tensions. Below a concentration of about 3 ml. per litre the respiration decreases. At concentrations between 1 and 2 ml. per litre they are killed. They are more resistant at 5° C. than at 15° C. and Stage V are more resistant than adults at both these temperatures.

7. Calanus can become acclimatised to salinities as low as 35–40% seawater (S=12‰–13.6‰), but their respiration is lowered at a salinity of 50%.

8. Light has a striking effect on Calanus. It may increase the respiration by 100% or more. This effect can be detected also in the sea, but not below 5 metres. Continuous exposure to light is harmful.

9. The bearing of these results on the distribution of Calanus is discussed.

10. From the amount of oxygen used in respiration, calculations of the food required are made and these are compared with the results given by Putter for Calanus and other copepods.
Digestion in the Plaice (Pleuronectes platessa)
Authors: Bayliss L. E.
Published: May 2009

1. It has been shown that the stomach of the plaice can digest proteins by an extra-cellular enzyme—apparently pepsin. Fats and carbohydrates appear to be unattacked in the stomach.

2. In the intestine, proteins are further attacked and the mucous membrane contains a trypsin and an erepsin.

3. The liver and the wall of the gall-bladder are more potent sources of trypsin than is the intestine; the former contains, also, a cathepsin, and the latter an erepsin. It is not certain whether any of these enzymes can be secreted into the intestine; administration of pilocarpine failed to make the bile definitely active in digesting proteins, but it is possible that there may be some other route by which the secretion may reach the intestine.

4. Fats and carbohydrates are digested in the intestine, since the mucous membrane of the intestine—and also the wall of the gall-bladder and the liver—contain lipase and amylase. The liver is a far more potent source of lipase than is either the gall-bladder or the intestine, but this lipase may be partly intra-cellular in action.

5. The hydrogen-ion concentration of the contents of the stomach and intestine has been shown to be consistent with the extra-cellular action of the enzymes found in the respective mucous membranes. The mucous membrane of the stomach is capable of secreting acid, and that of the intestine is capable of bringing about its neutralisation.
A Note on the Feeding Habits of Chimaera monstrosa
Authors: Newell G. E. , Roper H. D. G.
Published: May 2009

BashfordDean in his Monograph on the Chimaeroid Fishes (1906), describing the North Pacific species Chimaera colliei, states that it is omnivorous and that the “broken shells of mollusks are commonly found, as well as fragments of good sized crustaceans, as indeed the scanty literature records.” He further states that “in the gut of C. monstrosa Faber finds crustacean and shell-fish fragments; Monticelli, quoting Lütken, Cyprina islandica;hellips; Olsson finds also (and his observations are the most detailed hitherto published on the feeding of Chimaera) chætopods, amphipods, echinoids and polyps.”

The following is an account of the gut contents of several specimens of Chimaera monstrosa which the authors were fortunate enough to obtain recently.

The specimens which were taken from the Atlantic Ocean sixty miles N.W. of Black Eock (Lat. 54° N., Long. 12° W.) at a depth of 220 to 250 fathoms, were preserved in dilute formalin.

The actual examination of the gut contents was carried out as follows.

The œsophagus and rectum were ligatured, and that part of the gut lying between the two ligatures was removed and placed in a dish of dilute formalin. The gut was then opened by a longitudinal incision, and its contents carefully transferred to the dish where they were subsequently examined by means of a binocular microscope. The food fragments were then provisionally classified, care being taken not to separate such parts as may have belonged to the same organism during life.
On a new medusa, Amphinema krampi n.sp.
Authors: Russell F. S.
Published: May 2009

In a collection of plankton made by R.V. Sarsia, in a 2 m stramin ring trawl at 47° 12′ N., 7° 40′ W., on 21 July 1955 with 450 fathoms of wire out, there was a small anthomedusa which does not agree with any previously described species.
The size of diatoms: III. the cell width of Biddulphia sinensis Greville from the southern North Sea
Authors: Wimpenny R. S.
Published: May 2009

The present contribution deals with the measurements of fifty-two samples of Biddulphia sinensis collected by Hensen net hauls from the Ministry of Agriculture and Fisheries research ships George Bligh and Onaway, working in the southern North Sea between 1932 and 1938. With one exception in which there were only seventy available, the samples consisted of a hundred cells and the unit of measurement was that employed in Part I of this paper (Wimpenny, 1936). The dimension used was the greatest width (apical axis), and care was taken to see that the cells measured were lying flat, to give the true maximum of their elliptical cross-section. For convenience in tabulation and to avoid random fluctuations due to too small grouping of the data, the measurement units have been taken in pairs in the presentation of all the sea results, each arbitrary unit being equivalent to about 8 μ. The measurements from cultures, where the samples were sometimes fewer than a hundred, have been 4μ units.
Studies on marine flagellates: III. Three further species of Chrysochromulina
Authors: Parke Mary , Manton Irene , Clarke B.
Published: May 2009

Two of the new species of Chrysochromulina to be described here are somewhat more like the type species (C. parva Lackey) than were any of those included in our last communication (Part II of this series—Parke, Manton & Clarke, 1955). The diagnostic generic character of the presence of three filiform appendages arising close together is shared by all, and as before two of the appendages are flagella of equal or almost equal length and the third is a special organ to which the name haptonema has been given (Gr. åπτω to attach, υ⋯ματα pl. υ⋯ματα, a thread) (1955, p. 581). In our previous species the haptonemata when fully extended were relatively short, being not very different in length from the flagella. When not extended it was coiled in a flat spiral. Our three new species all have much longer haptonemata, of the order of twice the length of the flagella in C. ericina and three to five times the length of the flagella in C. ephippium and C. alifera.
The adhesive mechanisms of monogenetic trematodes: the attachment ofPlectanocotyle gurnardi(v. Ben. & Hesse) to the gills ofTrigla
Authors: Llewellyn J.
Published: May 2009

Little is known of the mechanisms whereby trematode parasites of fish gills attach themselves to their hosts. The adhesive apparatus consists of a posterior set of suckers or clamps supported by skeletal bars (sclerites) whose arrangement varies considerably in the different species. Yet though the pattern of these sclerites forms the main basis for the classification of the 200 or so species of the Diclidophoroidea into its six families, the only attempts to describe the mechanism of attachment of these parasites to their hosts appear to be those of Cerfontaine (1896), who described the attachment ofDiclidophora denticulatato the gills ofGadus viretis, and of Sproston (1945a) and Llewellyn (1956a), both of whom described the attachment ofKuhnia scombrito the gills ofScomber scombrus. In the present paper the mechanism by whichPlectanocotyle gurnardi(v. Ben. & Hesse) adheres to its hostsTrigla cuculusL., andT. lineataGmelin will be described.
The modes of action of toxic agents I. Observations on the poisoning of certain crustaceans by copper and mercury
Authors: Corner E. D. S. , Sparrow B. W.
Published: May 2009

Reports of recent attempts to discover how copper and mercury act as poisons to crustaceans are to be found in papers by Clarke (1947), Pyefinch & Mott (1948), Barnes & Stanbury (1948), Hoffmann (1950) and Russell Hunter (1950). Most of the evidence obtained has been interpreted in the light of two general theories (cf. Pyefinch & Mott, 1948). One is that these poisons exert their toxic effects by inactivating vital processes which occur at the animal's surface: the other is that they are absorbed by the animal and act internally by inhibiting metabolic changes. However, conclusive evidence supporting or excluding either possibility has yet to be obtained.
On the biology ofCalanus finmarchicusIX. Feeding and digestion in the young stages
Authors: Marshall S. M. , Orr A. P.
Published: May 2009

Little is known about the food of the nauplii and early copepodite stages of copepods, although it has usually been assumed that the food particles must be smaller and perhaps more concentrated than for adults. A few observations have been made on the feeding of the young stages ofCalanusin the laboratory, but none are available on feeding under natural conditions. It has been suggested (Marshall, Nicholls & Orr, 1934) that the success or failure of a brood ofCalanusin the sea might depend on the presence of a rich food supply during its development. Experiments were therefore undertaken to find what organisms could be ingested by the nauplii and early copepodite stages, how much of the different foods could be digested, and how much water they could filter in a day.
Amalosoma eddystonense sp.n., a new species of Bonelliidae
Authors: Stephen A. C.
Published: May 2009

In October 1921, a specimen of an echiuroid was taken in the otter trawl of the S.S. Salpa, in the neighbourhood of the Eddystone lighthouse. The specimen, a female, was provisionally identified by Mr E. Ford as Hamingia arctica Kör & Dan. The pharynx and uteri were opened in an unsuccessful search for males, after which the specimen was preserved in alcohol and put in the museum at the Plymouth Laboratory. In the following month, two more specimens were taken in the dredge by Dr R. S. Clark, a few miles from the same locality, and placed in the museum without further examination. No more specimens were obtained until April 1925, when one was taken in a trawl offRame Head, near the entrance to Plymouth Harbour. This specimen was examined by O. D. Hunt, and was found to be a female with uteri containing ripe eggs. Twenty-eight males of minute size were discovered attached externally to the female in a groove in the skin which extended for a short distance in the median line just posterior to what appeared to be a single genital orifice.
A preliminary investigation of the variation of vitamin B12in oceanic and coastal waters
Authors: Cowey C. B.
Published: May 2009

The presence in the sea of vitamin B12, or of its analogues, has been found necessary for the growth of several species of unicellular plants (e.g. Provasoli & Pintner, 1953; Droop, 1954, 1955).

Bioassays of the quantities in inshore waters during winter have been made by Lewin (1954) and by Droop (1954). The present investigation, carried out in 1955, was designed to extend this study and compare different seasons of the year.
On Keeping Medusae Alive in an Aquarium
Authors: Browne Edward T.
Published: May 2009

I have made several attempts to keep medusae alive in an aquarium, but have only recently been successful. A medusae when first placed in an aquarium swims actively about, but in a few hours it sinks to the bottom apparently tired out. After an interval of rest it takes another swim and again sinks to the bottom. This is repeated until the medusa becomes completely exhausted; then it stays at the bottom and slowly dies. In spite of every attention, plenty of clean sea-water, plenty of copepods, and a suitable temperature, I found that my medusae often used to die within a day of their capture.

When I have been watching medusae at the surface of the sea, I have noticed that they simply float along with the tide without often pulsating the umberlla. In my bell-jars the water was perfectly motionless, so that a medusa had to pulsate its umbrella in order to keep afloat, and as soon as the pulsations stopped it began to sink. There are some species, like those belonging to the Bougainvillidae, which live longer in confinement, as they are able to poise themselves in the water by the extension of their tentacles and remain motionless for long periods, but even these finally reach the bottom of the bell-jar, and a long period at the bottom ends in death.

It appeared to me that to keep medusae alive in an aquarium it was necessary to have the water in motion so that a medusae could float about just as it does in the sea, without having constantly to pulsate its umbrella.
Director's Report
Authors: Allen E. J.
Published: May 2009

The various researches detailed in my last Report, which are being conducted by the Association's Naturalists, have been continued during the winter. Mr. Garstang has been chiefly occupied in investigations relating to the migratory pelagic fishes, giving special attention to the characteristics of mackerel from different localities, some 1500 of these fish having been subjected to detailed examination in the course of this enquiry. The samples of mackerel have been obtained from the south-west of Ireland (through H.M. Inspectors of Irish Fisheries), from the North Sea and from America, in addition to those captured near Plymouth. As the results so far obtained refer only to the autumn fish, it has been thought better to defer their publication until after the coming spring fishery, when further samples from the same localities, as well as from the Mediterranean and from Norway, will be examined.

Mr. Garstang has also given much time to working out the results of the drift-bottle experiments, a report of which for the year 1897 will be found at p. 199. These experiments have proved more interesting and successful than we had anticipated when they were undertaken, and we purpose continuing and extending them during the coming year.

Mr. Holt's papers in the present number of the Journal represent but a portion of the many observations which he has been able to make during the year on the eggs and larvæ of fishes. He has also given much attention to the question of the distribution of fish at different ages in this neighbourhood.
Appendix
Authors: Stead F. B.
Published: May 2009

In the following Memorandum I propose to lay before the Sub-Committee of Enquiry, appointed by the Devon Sea Fisheries Committee, certain facts with regard to the contents of two of the bays on the South Coast of Devon, in which I have conducted trawling experiments, and then to point out the bearing of these facts on the practical questions before the Committee.
The Great Silver Smelt, Argentina silus, Nilss. An Addition to the List of British Fishes.
Authors: Holt Ernest W. L.
Published: May 2009

By the kindness of Mr. J. Jacobs, to whom the Laboratory is already indebted for many specimens of interest, I received on the 15th June a fine example of the species mentioned above, which had been trawled off the south coast of Ireland. The fish weighed 1 lb. 5 oz., and measured 42 cm., or 16½ inches. Though taken at least a day previously, it was in excellently fresh and firm condition. I have already recorded its capture in a letter to the Field and at a meeting of the Zoological Society, but the locality was inexactly given in each of these communications. I have since learned that the correct locality is 50° 20′ N., 8° 25′ W., or about seventy-five miles true S. of the Old Head of Kinsale, depth seventy-four fathoms. A number of the same species were trawled, and some were found to be excellent eating. I have no means of deciding whether the occurrence of A. silus on the ground indicated is normal or exceptional. If it can be taken in any quantity it should prove a valuable addition to our list of food-fishes.
On the Physiology of Amœboid Movement. I
Authors: Pantin C. F. A.
Published: May 2009

Of the relation of amœboid movement to other forms of contractility, very little is known at present. Hypotheses have been advanced to explain the movement, but they differ widely among themselves, and are founded almost entirely on direct observations of the normal activities of amœba. More recently Loeb (24) (25) and others have tried to determine therôleof various environmental factors, such as the presence of certain salts, in amœboid activity. It is on these lines that the present work is being conducted.
The Food of Plankton Organisms. II
Authors: Lebour Marie V.
Published: May 2009

Last year preliminary results on the feeding of some of the commoner plankton organisms were published (1922). Further progress is made this year, more especially on the living animals, chiefly cœlenterates, kept in the plunger jars. The results of these experiments, specially undertaken to find out whether medusæ naturally caught and ate small fishes, answer the question undoubtedly in the affirmative. A large number of the smaller medusæ were kept alive, and most of these were seen to catch and eat fishes. The usual method of catching the food is with the outstretched tentacles, which, drawn out to very fine threads, react when anything living touches them, stinging the prey with their stinging cells; the tentacles then contract and helped by others, and often also by the lips and sides of the umbrella, manage to convey the food to the mouth, from which it reaches the stomach and is digested. A certain amount of selection is apparent, for the tentacles often reject food. Moreover, medusæ of one species do not as a rule eat one another, although taking other species voraciously. If many small fishes are available the smaller crustacea are neglected by many of the medusæ, although these may be taken when other food is searce. Sagitta bipunctata and Tomopteris helgolandiea are popular with nearly all those that can eat fishes. Certain medusæ, e.g. Sarsia tubulosa and S. prolifera, have never been seen to eat anything but crustacea (copepods or decapod larvæ), and fishes have not been seen inside them.
The Silica Content of some Natural Waters and of Culture Media
Authors: Atkins W. R. G.
Published: May 2009

When studying the seasonal changes in the algal plankton in relation to the supply of the constituents necessary for their growth, one is led to seek the source of the silica used to form the valves of the diatoms and to consider whether lack of silica might be a factor limiting their multiplication.
Hydrographic Features of the Water in the Neighbourhood of Plymouth during the Years 1921 and 1922
Authors: Harvey H. W.
Published: May 2009

Data obtained during the cruises of the s.ss. Huxley and Oithona in the years 1903 to 1906 indicated a general seasonal movement of water into and out of the mouth of the English Channel. It was found that in the autumn, somewhat sooner or later and to a greater or less extent each year, water, of the high salt content characteristic of the open Atlantic in the north of the Bay of Biscay and to the south-west of the English Channel, began to move in a north-easterly direction into the mouth of the English Channel, extending in a tongue along the centre of the Channel and into the Irish Channel, which is characterised by water of lesser salt content.

This general movement of relatively high salinity water continued during the winter until the spring or early summer, when water of lesser salinity moved southward from the Irish Channel across the mouth past Ushant, and to some extent into the English Channel; the condition in August being that water of relatively high salinity which had entered the Channel during the winter months was cut off from Atlantic water of equal salinity by a less saline water-mass extending south from the Irish Channel.

These general movements have been deduced from the data collected during the cruises in February, May, August, and November. To accurately depict the changing conditions and follow the movement of the water year by year would require frequent observations, more or less simultaneous, over a wide area—a condition of perfection which in practice could not be obtained without the use of several ships working almost continuously and in conjunction.
Plymouth Peridinians. IV. The Plate Arrangement of some Peridinium Species
Authors: Lebour Marie V.
Published: May 2009

The well-known Peridinium ovatum (Pouchet) is a common and widely distributed species. It was first described by Pouchet (1883) from the Mediterranean, and later more detailed figures were given by Schütt (1895), Fauré Fremiet (1908), and Broch (1909). None of these figures agree with the plate arrangement found in the specimens from Plymouth. Jörgensen (1913) places the species in his section Humilia in the group Metaperidinium, on account of the supposed arrangement of the dorsal epithecal plates.
The Size of Diatoms. I. The Diameter Variation of Rhizosolenia Styliformis Brightw. and R. Alata Brightw. in Particular and of Pelagic Marine Diatoms in General
Authors: Wimpenny R. S.
Published: May 2009

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.
Rearing Animals in Captivity for the Study of Trematode Life Histories. I. Larus Ridibundus L., the Black-headed Gull
Authors: Rothschild Miriam
Published: May 2009

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.
Part II. Zooplankton-herring Correlations in the English Fisheries
Authors: Lucas C. E.
Published: May 2009

The English fisheries which were investigated with the Plankton Indicator in 1931,1932, and 1933 were divided into three areas, i.e., those off Shields, the Humber mouth and the East Anglian coast (this last fishery was also sampled in 1930). All the samples in the Shields area lie between 56° 00 N. Lat. and 54° 20 N. Lat., whilst the majority (80%) lie in the area between 54° 45 N. Lat., and 55° 30 N. Lat. and a line parallel to and some 40 miles from the coast. This is an area of some 1600 square miles. In the Southern Bight Lat. 53° 00 N. was taken as a division between the Humber and the East Anglian areas. The distribution of all the samples is shown in Figs. 1 to 4. With the exception of the samples obtained by the Ministry of Fisheries research ship Onaway in June, 1931, and four samples obtained by H.M.S. Chenoell in September, 1933, all those in the Shields area have been collected by individual drifters engaged in the fishery. The Humber and East Anglian samples were obtained from both drifters and gunboats of the Fishery Protection and Mine Sweeping Flotilla alongside drifters fishing. The manner of collecting these samples has been described in Part I (p. 153).
Studies in the Physiology of Commensalism. III. The Polynoid Genera Acholoë, Gattyana and Lepidasthenia
Authors: Demorest Davenport
Published: May 2009

The commensal polynoid Acholoë astericola (Delle Chiaje) exhibits a powerful positive response on contact with its host, Astropecten irregularis (Pennant). This response is only relatively specific, Acholoë demonstrating it to a number of starfish that do not serve as host in Plymouth waters.

All living host tissue has some attraction for the commensal; and the attractant is apparently released in quantity in the stomach of the host.

Passage of time (apparently as long as tissue remains alive) and chilling do not markedly alter the attractiveness of isolated host tissue. Temperatures above 450 C. alter or abolish its attraction.

The extreme instability of the attractant has so far made it impossible to demonstrate its presence in extracts.

Evidence is presented that the attractant is rapidly oxidized.

Experiments with the scale-worms Gattyana cirrosa (Pallas) and Lepidasthenia argus Hodgson, commensal respectively with Amphitrite johnstoni Malmgren and A. edwardsi Quatrefages, indicate that a chemotaxis to the host may be of relatively minor importance in governing the behaviour of these commensals.
The biology of Asterias rubens L.V. A Porphyrin pigment in the integument
Authors: Kennedy G. Y. , Vevers H. G.
Published: May 2009

A porphyrin pigment found inAsterias rubenshas been re-examined and found to be protoporphyrin, and not haematoporphyrin as originally reported by MacMunn. The pigment was identified by spectroscopic and spectrophotometric observations as well as by chemical tests and the use of paper partition and column chromatography. The protoporphyrin is absent from the gut, gonads and digestive caeca, and is present only in' the leathery integument.

The porphyrin occurs in the integument as free protoporphyrin; a yield of 33-6 mg. of red crystalline protoporphyrin dimethyl ester was obtained from a sample of 5485 g. ofAsteriasintegument.

The relative amounts of protoporphyrin in different coloured specimens ofA. rubenswere determined by a fluorimetric method. With four well-defined colour types the amount of porphyrin per gram of integument was found to decrease rapidly in the series: violet-brown, dark brown, red and pale.

Neither protoporphyrin nor a porphyrinogen was found in the soft parts ofChlamys opercularisorMytilus edulis, the main food animals ofAsteriasin the Plymouth area. The exact source of the integumentary porphyrin in this starfish is therefore uncertain, ,but it is suggested that it may be derived from the chlorophyll pigments found in the digestive caeca.

The porphyrin does not contribute materially to the colour pattern of the animals, most of whose colour is carotenoid, and it is most likely that it is a by-product of excretion formed from chlorophyll.
The Regeneration of the Siphons ofCiona IntestinalisL.
Authors: Sutton Muriel F.
Published: May 2009

Regeneration of the siphons of normal specimens Ciona intestinalis has been found to be completed, in every particular other than that of length, in 4 days.

Removal of the neuroglandular complex retards the regeneration rate.

With the exception of the epidermis and of the basic tunic, the new structures differentiate from haemoblasts.

A tentative synthesis has been made of the information available upon asexual reproduction and regeneration in the Ascidiaceae.
The Settlement of Ophelia Bicornis Savigny Larvae. The 1951 experiments
Authors: Wilson Douglas P
Published: May 2009

Further tests on the settlement reactions of Ophelia bicornis larvae have shown that both Bullhill Bank and Salthouse Lake sands are less favourable to the larvae after sterilization than they are when fresh and untreated. The effect of a large variety of treatments of both sands has been investigated under conditions where the larvae were free to choose between two or more samples of sands presented together in the same dish. Results from these experiments, taken in conjunction with results obtained using conical vessels, show that sands may be classed as attractive, neutral or repellent with intermediate grading between these three main categories. It is concluded that organic material, living or dead, on the sand grains plays an important role in rendering a sand attractive or repellent to the larvae.
Diurnal Variations in the Grazing of Planktonic Copepods
Authors: Gauld D. T.
Published: May 2009

Records were made of the presence or absence of food in the guts of Calanus finmarchicus caught in three different depths, at intervals of 4 hr. through 24 hr. It was found that 80-100 % of the Calanus caught at the surface were full of food at all hours of the day.

The number of Calanus containing food in deeper water was distinctly less. This may be correlated with the abundance of its food close to the surface. Diurnal vertical migrations took place on some occasions when samples were taken, but not on all.

In the absence of vertical migration Calanus was abundant at the surface and feeding continuously at all hours of the 24 hr. Where vertical migration took place feeding was mostly at the surface and was restricted to the hours of darkness, i.e. in summer to a period distinctly less than 8 hr. round midnight. Laboratory observations confirm the absence of any feeding rhythm.
Synthesis of Organic Nitrogen and Chlorophyll by Nitzschia Closterium
Authors: Harvey H. W.
Published: May 2009

Experiments have been made with the marine diatom Nitzschia closterium grown in artificial light with different nitrogen sources.

After the nitrogen source in the medium was exhausted, photosynthesis and cell division continued, the cells becoming nitrogen- and chlorophylldeficient.

On adding a nitrogen source to deficient cells and storing in darkness, synthesis of organic nitrogen, mostly water soluble, proceeded rapidly from ammonium, less rapidly from nitrate and very slowly from nitrite, with which it grows in light as rapidly as with nitrate or ammonium nitrogen.

Possible reasons why nitrate but not nitrite is reduced in the dark are discussed.

Chlorophyll and yellow pigments were synthesized in the dark by nitrogendeficient cells in quantity related to the organic nitrogen synthesized.

Chlorophyll was synthesized in small amount by non-deficient cells which had been growing rapidly before transfer to darkness. Cells contained less chlorophyll when grown in moderately bright than when grown in dim light.
Seasonal Variations in the Phosphate and Silicate Content of Sea Water. Part VI. 1948 Compared with the 1923–25 Period
Authors: Atkins W. R. G.
Published: May 2009

The fifth paper of this series (1930) was the author's last, after which the work was handed over to L. H. N. Cooper. It was resumed by the author in 1948 to compare the early years with the post-war, since the determinations had lapsed. Measurements of the extinction coefficient of the water were also resumed, and it was desirable to obtain the chemical data at precisely the same time.

The phosphate results are, as before, expressed as P2O5 in mg./m.3, since for crop calculations this old unit is convenient; to convert to mg. P, which is more rational, multiply by 0437; to bring to milligram atoms multiply by 0–0141. The analyses have not been corrected for salt error, since the early results were not^ and the factor for this correction has not as yet been agreed upon.

The silicate results are given as mg./m.3, of SiO2, but though the standard used in Plymouth was checked for me by Dr E. J. King in Canada and agreed with his (King & Lucas, 1928), yet a different value had to be assigned to the silica factor of the picric acid solution. All values have accordingly been multiplied by I.44.

The phosphate results for E1, surface, from 11 February 1948 to 1 February 1949 are shown in Fig. plotted against the dates.