said, we hear of new discoverers who promise more or less infallible results, but close examination of their specifics shows their worthlessness. Within the last year or two chemical therapeutics had received a fresh impulse of scientific value owing to the results of experiments on animals, and it was now tolerably certain that blood treatment must take the place of the former treatment of stomach and intestines. Turning to rav therapeutics, Prof. Czerny admitted its efficacy after the knife in removing injuries, but was not inclined to attach very great importance to electricity applied as rays. In his opinion the more remedies we are confronted with the more difficult it is to find one's way to a proper treatment. This, he said, should be the work of the numerous institutes springing up in various civilised lands the express object of which is the study of this terrible scourge. On the whole, says the correspondent of The Morning Post, the address was couched in rather pessimistic tones, and the lecturer did not seem to share the hopeful views which have been lately expressed regarding the chemical, as opposed to the operative, treatment of the disease.

IN The Popular Science Monthly for August Prof. Richard Pearce gives an interesting historical survey of research in medicine, and Dr. Heinemann discusses cold-storage problems. The latter states that with careful treatment there are no appreciable differences in chemical composition between fresh meat and meat kept frozen for a period of two years.

IN the Farmers' Bulletin, No. 487 (U.S. Department of Agriculture), by Dr. Langworthy and Caroline Hunt, cheese and its economical uses in diet are considered. A number of recipes for the preparation of cheese dishes is given, and it is stated that cheese does not differ materially in its digestibility from meat, and, weight for weight, contains rather more protein and 50 per cent. more fat than cooked beef, and hence is a valuable food.

We have received the August and September numbers of The Child, a monthly journal devoted to child welfare. Each contains a number of articles of general and special interest to those who have to deal with children-parents, educationists, doctors, and health visitors-notably one by Dr. Mary Scharlieb on adolescent girls from the point of view of the physician, in which the characteristics and management of adolescent girls are critically considered.

DETAILS are given of an improved respiration calorimeter, and the results of experiments with it by the U.S. Department of Agriculture (Exp. Station Record, vol. xxiv., No. 7, and Year-book for 1910). The influence of mental activity on metabolism was one of the subjects investigated, and in half the cases at least sustained mental effort had no positive influence upon the transformations of matter and energy within the body. The gaseous exchange and energy metabolism during the ripening of picked fruit, the germination of seeds, and the incubation of eggs are other subjects under investigation.

IN the August Fortnightly Review, Mr. Adolphe Smith discusses the present menace of cholera. He points out how cholera has been more or less prevalent on the Continent in various districts during the last three or four years, and directs attention to the danger that exists of the introduction of the disease into this country, particularly by way of some of the smaller ports, where sanitary administration is still very inadequate. He pleads for the establishment of a Ministry of Public Health, and for the burden of port sanitary administration to be placed on the country as a whole, and not on the local authority. Finally, he maintains that despite improvements in water supply, sewage disposal, and general sanitary conditions, poverty is the most potent of all those grim allies that join together to render devastating epidemics possible!

A RECENT number of the Annals of Tropical Medicine and Parasitology (vol. vi., No. 2) contains the results of investigations by H. B. Fantham and Annie Porter upon the destructive bee disease commonly known as "Isle of Wight Disease," together with a detailed description of the parasite and its life-history. The parasite, Nosema apis, belongs to the order Microsporidia, and is a close ally of N. bombycis, the parasite of silkworms, which causes the disease only too well-known as "pebrine," the subject of memorable researches by Pasteur. The method of infection was found to be contaminative; hereditary infection through the egg, as in N. bombycis, though by no means improbable, has not yet been proved to occur. The only certain means of destroying the resistant spores of the parasite and eradicating the infection is by fire. It is to be regretted that the authors should have thought it necessary to complicate the bibliography of Protozoa, already sufficiently vast, by setting forth their important results in three distinct and separate memoirs, which, as they are printed successively in the same journal, might easily have been included under one title.

MR. LUDWIG GLAUERT describes, in the first volume of the Records of the Western Australian Museum and Art Gallery (Perth, 1912, p. 47), an important series of remains of extinct marsupials from Balladonia. Eight of the species have not been recorded previously from Western Australia. The author supports Owen's view that Thylacoleo, the "marsupial lion," was carnivorous, and illustrates the worn enamel of its incisors.

To the July issue of The Agricultural Journal of India Mr. T. B. Fletcher, entomologist to the Madras Government, communicates an article, illustrated by a coloured plate, on termites or white ants. At the commencement reference is made to the modern view that these insects are not Neuroptera, but are more probably related to cockroaches and other Orthoptera, termites and cockroaches having many structural peculiarities in common. Then follows a full account of termite social economy.

A SHORT time ago the editor of Popular Mechanics (U.S.A.) conceived the idea of taking the votes of a

number of scientific men on what inventions they considered to be the "seven wonders of the modern world," and for this purpose a list of numerous inventions was circulated, from which seven had to be selected. The result is published in the August number, and the seven inventions which received the highest number of votes are as follows:-Wireless, telephone, aëroplane, radium, antiseptics and antitoxins, spectrum analysis, X-ray.

We learn from the daily Press that considerable anxiety is felt in France regarding the frequent deaths that have recently occurred through eating poisonous fungi. Three precautionary measures are suggested. One is to avoid gathering mushrooms having a persistent volva at the base of the stem; another is to boil every mushroom in water with a little salt; and a third is to have some animal charcoal at hand to be swallowed when a case of poisoning occurs. It is stated in the notices that no species is poisonous in which the volva is absent. It would be, however, wrong to regard all such species as esculent, for several well-known kinds having this characteristic certainly produce temporary, if not fatal, poisoning, at least unless subjected to prolonged boiling.

Two useful lists of South African plants have recently been published. Mr. J. Burtt-Davy and Mrs. Reno Pott-Leendertz (Annals of the Transvaal Museum, vol. iii.) have compiled a "first check-list' of the flowering plants and ferns of the Transvaal and Swaziland, enumerating about 3300 species. Mr. F. Eyles (South African Journal of Science, vol. viii.) gives a preliminary list of the plants of southern Rhodesia, comprising about 1700 flowering plants and ferns.

A NEW and curious species of "ground bean" (Kerstingiella geocarpa, Harms) from tropical West Africa is described and figured in the Kew Bulletin, No. 5, 1912. When the flowers are fully developed they are close to the ground, and after fertilisation the hitherto short stalk of the ovary lengthens into a long "carpopodium," which turns down and drives the young pod into the ground, where it matures. The same number contains a description and fine plate of a remarkable new spurge (Euphorbia multiceps, Berger) received at Kew from South Africa; it resembles a green pineapple with a number of spikes protruding irregularly from it, the stout fleshy axis being densely covered with short coral-like horizontal branches-the spikes are barren inflorescences, but no flowers have been seen. There is also a useful compilation of the various timbers and trees to which the terms tulipwood and tulip tree have been applied, just as other names (gum, rosewood, cedar, pine, mahogany, &c.) are indiscriminately applied to diverse timbers and trees.

MR. CECIL H. HOOPER has contributed to Irish Gardening for June and July an account of some interesting experiments on the pollination of hardy fruits, made by himself, Mr. F. Chittenden, and others. These experiments were made in order to ascertain whether fruits can set and mature without

the aid of bees, whether mature fruit can be obtained by pollination with the pollen of the same variety or the same flower, and whether better fruits result from pollination with pollen of another variety. It was found that gooseberries and currants, raspberries and loganberries, though freely self-fertile, set better fruit when visited by bees; that strawberries are apparently to some extent wind-pollinated, though this needs confirmation. As is well known, more or less complete self-sterility is common among the many varieties of cherry, plum, apple, and pear; in the majority of cases pollen from another variety is essential for fruit formation. Details are given of numerous interesting results obtained by covering otherwise untouched flowers with muslin bags, by brushing with pollen from the flower's own anthers or from those of other plants of the same variety, and by pollination with pollen from other varieties. In connection with the interplanting of different varieties in orchards, lists are given according to the times of flowering. The author estimates that about 80 per cent. of the pollination of hardy fruits is done by the hive bee, about 15 per cent. by the various humble bees, and the remainder by miscellaneous insects.

THE meteorological year-book for Bremen, 1911, one of the regular German series, contains two important summaries in addition to the observations for the year in question (1) A discussion of the daily maximum and minimum temperatures for 1890-1910 (twenty-one years) by Mr. J. Siedenburg; and (2) monthly tables of the climate of Bremen for 1876-1910 (thirty-five years). This long series gives an absolute maximum temperature of 93'9° in May and an absolute minimum of 130° in December, but a reading of -17′1° is quoted as having occurred on January 23, 1823. The heat and drought of 1911 lasted from July 4 to September 27 (twelve weeks). Prof. Grosse ascribes the abnormal conditions principally to the shifting of the Azores pressure maximum to the north-east, and possibly to some extent to the approximate occurrence of the minimum sunspot period.

IN the Atti dei Lincei, xxi. (2), 2, Prof. Augusto Righi describes experiments on the convection of ions produced by magnetic or magneto-kathodic rays. According to the author's hypothesis these rays cause some of the electrons to unite with positive ions, the combination behaving like a double star or the system formed by a planet and its satellite. Once formed, they are carried by magnetic action from regions of greater to regions of lesser magnetic force, where the clements again frequently become dissociated. To dectect the presence of these ions, Prof. Righi makes use of a small cylinder of paper suspended by a fibre in the magnetic field generated by a second induction coil. According to theory the ions, by their impact on the cylinder, should cause the latter to rotate in the same direction as the magnetising current of the coil, and this was observed to be the case.

CERTAIN formulæ relating to the pressure of fluids on oblique planes have been recently quoted as "Avanzini's law." Col. de Villamil has made several inquiries as to where these laws were published, and having failed to obtain the information from others,

has taken the matter up himself, and publishes an abstract of Avanzini's work in The Aeronautical Journal for July. The work in question was published in the Memorie dell'Istituto nazionale italiano at Bologna early last century, and deals with experiments on the relations between the velocity of a plate in still water, the angle of attack, the position of the centre of pressure, the density of the fluid, the length and breadth of the plate. The paper is illustrated by copies of the original diagrams, and contains experimental data. There are, however, several errors which require correction in the formula.

THE annual report of the results of sight tests in the Mercantile Marine, for the year ending on December 31, 1911, just published as a Parliamentary paper (Cd. 6370), shows a slight increase in the percentage of failures, both in form and in colour vision, over the returns of the preceding year. 7309 candidates were examined, with 117 failures in form vision, none of whom were re-examined, and with 192 failures in the first examinations for colour vision, of whom 56 passed on re-examination. This gives a percentage of 189 failures in colour vision, as against 151 in 1910, and is the largest proportion yet recorded. The methods of testing employed were the same as in 1910, the recommendations of the Departmental Committee appointed in that year not having yet been acted upon. Those recommendations included the substitution of a dark brown test skein for the deep red at present in use, and the employment of a special lantern, designed by the committee, for all candidates. Preparations are being made to carry these alterations into effect at the earliest possible time, and they seem calculated to meet all reasonable objections to the tests hitherto employed. An article on the report of the committee appeared in NATURE of July 4 (vol. lxxxix., P. 453).

VOL. v. of the Journal of the Municipal School of Technology, Manchester, a record of investigations published by the staff and students during 1911, extends to nearly 300 pages. Like its predecessors, it shows the unique position as a centre of research in applied science occupied by the Manchester School amongst the technical schools of this country. Three of the nineteen papers reprinted deal with pure science, and of them that by Prof. Gee and Mr. Adamson, describing a neat and simple "dioptriemeter" for measuring the focal lengths of lenses by the deviation produced, may be specially mentioned. Of the technical papers, the most important are that on electricity meters, by Messrs. Ratcliff and Moore, read before the Institution of Electrical Engineers, that on the electrical theory of dyeing, by Mr. W. Harrison, who finds in the theory explanations of many facts previously not interpreted, and that on boiler economics by the use of high gas speeds, by Prof. Nicholson, who shows how boilers may be reduced in size about 30 per cent. without any diminution in their steam production. The journal is printed in the printing crafts department of the school, and its execution does credit to that department.

UNDER the title of "Geostatic Funiculars," Prof. A. F. Jorini, writing in the Rendiconti del R. Istituto

lombardo, xlv., 13, gives a solution of the problem presented by a cylindrical tunnel subjected to earth pressure, the surface of the superincumbent earth being horizontal.

PROF. C. MATAIX's papers on aëroplane stability in the Revista de la Sociedad matemática española conclude with the July number. The author succeeds in satisfying the conditions for longitudinal but not lateral stability. The latter failure is due to the character of the systems of surfaces assumed in the investigation. If the author had studied a system furnished with two vertical auxiliary surfaces or fins, he would have had no difficulty in satisfying the necessary conditions, and it is to be hoped that readers of the paper will not accept the conclusion that all systems of planes are laterally unstable.

In a paper read recently by Mr. Edwin O. Sachs, at the New York International Congress on the testing of materials, the author directs attention to the very small amount of scientific testing of reinforced concrete which has been carried out in Britain. Our public institutions have been very remiss, for there is practically nothing to place beside the elaborate researches carried out by engineering professors in the public laboratories of the United States, Germany, and France. The author thinks that it is almost hopeless to expect our Government or our engineering colleges to pay now any attention to the matter, so that we can only look for a continuance of the efforts of private bodies, such as the professional societies intimately concerned.

OUR ASTRONOMICAL COLUMN.

GALE'S COMET, 1912a.-The comet discovered by Mr. Gale on September 8 is apparently becoming brighter and travelling northwards. A second telegram from Kiel states that it was observed at Santiago on September 11, when its position at 7h. 49'2m. (Santiago M.T.) was :

R.A. = 13h. 54m. 2'4s., decl. = 33° 10' 50" S. Comparing this with the position at the time of discovery, we see that the comet moved about 4° 15' to the east and 3° 20′ northwards in a little more than two and a half days. In a telegram announcing the discovery, Reuter's Agency gave the magnitude as 6; the Santiago observer reports it as 5, so that there is a possibility of the comet becoming a more or less conspicuous object in our evening sky. When discovered, the comet was about half-way between and Centauri, and is apparently travelling towards the neighbourhood of a Libræ; this region now sets at about 7 p.m.

In the Astronomische Nachrichten (No. 4601) Herr Prager describes the object seen at Santiago as round, diameter 2', magnitude between 3 and 6, nucleus, no tail.

THE TOTAL SOLAR ECLIPSE OF OCTOBER 10.-From The Observatory, No. 452, we learn that the eclipse party from Greenwich, consisting of Messrs. Eddington and Davidson, with Mr. J. J. Atkinson as a volunteer, left for Brazil on August 30. They expect to make their observations from Christina, some 150 miles inland from Rio de Janeiro, and the programme includes the direct photography of the corona, the photography of the ultra-violet spectra of the corona and chromosphere, and an attempt to secure mono

chromatic photographs of the corona in the light of the corona line (5303). The observing station is some 3000 feet above sea-level.

In

THE PERSEID SHOWER OF METEORS.-His watches for meteors on August 10 and 11 having disclosed but very meagre displays, Mr. Denning is led to believe that something must have intervened to bring about a very marked decline in the splendour of this noted shower. In a table, appearing in No. 452 of The Observatory, he shows how very few Perseids are now seen as compared with a decade ago. 1901, during two watches of 6 hours in all, he saw 104 Perseids, in 1907 (6 hours) he saw 101, and in 1909 (4 hours) 79. Last year only three Perseids were seen in 24 hours, while this year only fourteen rewarded his two watches of 2 and 1 hours respectively. The conditions were not good, but, when compared with the 252 Perseids seen in 4 hours in 1874, and 285 in 5 hours in 1877, it would appear that something more than poor observing conditions must be held accountable for the poverty of recent displays.

THE SOLAR CONSTANT AND CLIMATIC CHANGES.-In a third paper on climate and crops, published in the Bulletin of the American Geographical Society for August, Mr. Henryk Arctowski compares the temperature records made at Arequipa during the period 1900-10 with the Washington values for the solar constant, and finds evidence of agreement between them; he also shows that Arequipa is not exceptional. His results indicate that a departure of 1° F. in the monthly mean observed at Arequipa is due to a departure, of about o'015, of the solar constant from its normal value. If this be true, a comparatively small, but permanent, lowering of the constant would account for such climatical conditions as existed during the Pleistocene Ice age. Mr. Arctowski also finds that the oscillations of temperature found in his data correspond to those of atmospheric pressure to which Lockyer assigned a mean period of 38 years. THE LEEDS ASTRONOMICAL SOCIETY.-The Journal and Transactions (No. 19) of this society for 1911 contains reports of a number of papers read before the society. Among others, there is an interesting discussion of the mutual eclipses of the satellites of Jupiter, by Mr. Whitmell, a paper dealing with suitable observations for amateur astronomers, by Mr. Ellison Hawks, and a discussion of the structure and sidereal significance of nebulæ by the Rev. Ivo Gregg. The membership now totals seventy-five, and the average attendance at meetings is fourteen. THE PERIOD AND ORBIT PERSEI. From measures of a number of radial-velocity spectrograms, secured at the Potsdam Observatory between 1900 and 1908, Dr. A. Hnatek has derived an orbit for the spectroscopic binary a Persei, which he publishes in No. 4599 of the Astronomische Nachrichten. The variability of the velocity of this star, although small, now appears to be established, and Dr. Hnatek's results indicate a very short period of 40938 days. The radial-velocity of the system is -343 km., the eccentricity of the orbit o'47, and the length of the semi-major axis of the projected orbit 46,000 km.

MR.

OF

a

NEW RULES FOR LIFE-SAVING APPLIANCES IN BRITISH SHIPS. R. BUXTON has lost no time in considering and giving effect to the recommendations made by Lord Mersey and his colleagues, as well as the report of the Advisory Committee. The character of these recommendations and of that report has been described

fully in previous issues (see NATURE, August 8 and 29); it will suffice, therefore, briefly to indicate the most important points in the Parliamentary Paper (Cd. 6402) issued a few days ago, in which the new rules made by the Board of Trade are contained. Those rules will not have statutory effect until they have lain on the table of the House of Commons for

forty days, and it is not proposed that they shall come into effect until January 1, 1913. It is practically certain that when Parliament reassembles the rules will be criticised, and it is possible that they may be amended in some respects as the result of that criticism.

Although the rules previously issued have been accepted without serious challenge, the circumstances of the present revision and the drastic nature of some of the new regulations may cause a departure from precedent. Mr. Buxton has recognised the special conditions of the revision of the rules, and has wisely prefaced them by an explanatory memorandum which His is both comprehensive and clearly expressed. memorandum gives the history of the steps which have been taken by the President of the Board of Trade to deduce all possible lessons from the loss of the Titanic in order to secure greater safety in future for life and property at sea.

It is also, in effect, an attempt to justify the rules themselves in those features wherein the report of the Advisory Committee has been departed from. That report has been dealt with somewhat harshly by critics, who are disposed to think that shipowners serving on the committee have been unduly influenced by consideration of their class-interests. There is no real foundation for such an opinion, and Mr. Buxton marks his dissent therefrom by stating that, although he has been unable to adopt the conclusions of the committee on some material points, its report has been of very great value, and that he desires to express a high appreciation of the time "and pains expended by the members of the committee and of its various subcommittees on the important questions referred to them." Nothing but prejudice could lead to the conclusion that the shipowners and shipbuilders, who have given gratuitous and unstinting service on these inquiries, would have allowed personal considerations to weigh with them. On the contrary, it is clear that no classes of the community can have a greater interest in securing safety at sea, and certainly no other persons have done so much during the last twentyfive years to increase that safety.

The main point of difference between the Advisory Committee and the new official rules is to be found in the provision that foreign-going passenger and emigrant ships are in future to have sufficient lifeboat accommodation for all on board; whereas the committee recommended that lifeboats should be supplemented by rafts, collapsible boats, &c. It is intended further to consider the extent, if any, to which liferafts may be used when the report of the Davits and Boats Committee-which is about to commence its labours has been received. Collapsible boats are not to be included in future estimates of life-saving accommodation, although they may be continued in use in existing vessels for a certain period not specified. On this point there will be debate, and there is reason for difference of opinion. Whatever the final decision may be, it should be noted that there is now universal agreement that in all cases, even in the best subdivided foreign-going ships, every soul on board shall have a chance of keeping afloat in boats, rafts, or other appliances, in case a ship founders through collision, grounding, or other accident. For ships in the home trade less stringent provisions are insisted upon in respect of life-saving accommodation, and this course

is reasonable having regard to the restricted range of their employment and the greater chance of external help in case of accident.

What remains to be demonstrated-and the task will not be an easy one-is whether the large number of lifeboats now thought to be essential can possibly be so carried as to be loaded and got into the water safely within a reasonable time after an accident has taken place-say within half an hour or an hour. Judging by the Titanic-in which case all the circumstances were most favourable to the loading and lowering of boats-radical changes will be required in the installation of lifeboats and in the means of lowering them, if this essential condition is to be fulfilled. All that need be added is that whatever may be the number of lifeboats carried, and however efficient may be the details of the arrangements for lowering these boats, it is obviously of primary importance to secure efficient watertight subdivision in passenger ships, so as to minimise the risk of foundering and to lengthen out the time which ships will remain afloat in cases of accidents so serious as to involve their final sinkage. On this matter another committee is still at work, and no action can be taken by the Board of Trade until its report has been presented.

IN

ATMOSPHERIC PRESSURE AND

TEMPERATURE.

N Aus dem Archiv der deutschen Seewarte, 1911, No. 4, W. Brockmöller discusses the geographical distribution of the monthly range of oscillation of the barometer. So far as the southern hemisphere is concerned, the question was thoroughly investigated by Dr. W. J. S. Lockyer in a recent publication of the Solar Physics Committee, but Herr Brockmöller's treatment of the subject covers a wider area, and is based on a different definition of the "range."

He takes as the measure of this the mean value of the difference between the highest and lowest barometer readings for each month, and deals with a selection of stations, about 300 in all. After correcting the values for the periodic semi-diurnal variation, and for height above sea-level in the case of a few high-level stations, he plots the values for winter (DecemberFebruary), and for summer (June-August), and obtains two very interesting charts, showing the isobarometric lines, or lines of equal range. For the northern hemisphere he obtains also normals for different latitudes, and draws the isanomalies, or lines of equal departure from normal. The range is least, 3 or 4 mm., in the equatorial region, and greatest near the arctic circle, apparently diminishing again towards the pole. The outstanding features are the maxima, in both seasons, near Iceland and the Aleutian Islands, the regions of the "permanent cyclones." The maxima are naturally much less intense in summer than in winter. Perhaps even more remarkable is the large value of the anomaly on the east coast of North America, where it is greater than at any other place. The effect is possibly due to the proximity of the division between the Labrador current and the warmer water of the North Atlantic, but it is deserving of further investigation.

In the same journal, No. 5, Prof. Köppen and Dr. Wendt discuss the vertical distribution of temperature over Hamburg between the earth's surface and a height of 3000 m. The records obtained in nearly 1200 ascents of kites and balloons during the years 1904-9 have been analysed very thoroughly, and a new departure has been made in the special treatment of so-called inversions of temperature-gradient. The authors find that such inversions occur in 69 out of

every 100 ascents, the temperature remaining constant or increasing with altitude. Inversions are most frequent in autumn and winter, and in December they are found in nearly every ascent. At all seasons they occur most frequently with southerly winds. Inversions in which the increase of temperature exceeds 3° C. are almost invariably accompanied by a decrease in the relative humidity except for those which occur in the layer between the earth's surface and a height of 500 m. At all seasons the sky is more frequently cloudy than clear on the occasions when inversions are recorded, but in spring and autumn the number of cases of clear sky is large. The clouds were found usually to have their lower surfaces below 500 m., except in those cases in Another which inversions occurred below 500 m. section of the paper deals with the dependence of temperature-gradient on wind direction. Near the surface the gradient is greatest with N. winds, above 500 m. with W. winds, and above 1000 m. with Š.W. winds. As the wind usually veers with increasing height, it seems probable that the actual direction of the current for maximum gradient in the layer considered will be northerly at all heights.

PLANKTON INVESTIGATIONS.

N the Bulletin Trimestriel, 1911, the second part IN of the "Résumé des Observations" continues the summary of the plankton investigations carried out under the international programme in the north-east Atlantic and north-west European waters during the years 1902-8. The subjects here dealt with are the Copepoda, Tunicata, Ostracoda, Chætognathan Amphipoda, Rotatoria, and Ceratium. With the vast amount of material collected in course of the investigations external records are incorporated in a discussion of the seasonal occurrence and distribution of the species considered, and the hydrographic conditions associated in each case with such. The annual and seasonal distribution and intensity of many of the more important species are shown in a number of separate charts. From an economic point of view, attention is directed to the importance of many of the Copepoda and Amphipoda as constituting in a large measure the food supply of Clupeoids, Gadidæ, the mackerel, and other marketable fishes.

As bearing directly on questions of physical oceanography, Salpa and Doliolum among the Tunicata afford important examples of warm-water species drifted as annual visitors to our coasts by the agency of the Gulf Stream. Similarly, several species of Ceratium show a distribution largely increased by immigration through the Faroe-Shetland Channel into the North and Norwegian Seas and beyond. Some of the latter species have a second sphere of distribution in the West Atlantic, from Florida to Newfoundland, and the author of this section, who has traced some of them sparingly at wide intervals across the Atlantic to the American coast, is of opinion that the two spheres of distribution are indeed in communication by virtue of the east-going oceanic movement. Conversely, among the brackish-water Rotatoria, species find their extension during the summer months from the Gulfs of Finland and Bothnia over the Baltic and outwards, mainly dependent on the periodic surface outflow of low-salinity water in this region. For the further elucidation of these complex problems, more exact information is required concerning some of the more critical species, and the need is felt, in particular, for a greater extension of the area of investigations to the westward and south-westward of Ireland.