principal opening and two smaller lateral openings (Tripylea), while others have a larger number of openings regularly or irregularly disposed (Sporopylea). Notwithstanding its peculiar structure and conspicuous size, the central capsule of all Phæodaria, has merely the histological value of a single simple cell. This is shown by the microchemical condition of its protoplasmic contents and the nucleus inclosed within it. This cell-nucleus (described by me in 1862 as the "inner vesicle") is vesicular and of large size, being usually more than half the diameter of the central capsule. It sometimes includes one large nucleolus, sometimes several.

The extra-capsular soft substance of all Phæodaria is distinguished by two characteristic peculiarities-first, by the large quantity of the extra-capsular sarcode, which is more voluminous than the intra-capsular, and secondly by the mass of phæodella or “dark pigment granules" which it contains. The colour of the latter is usually dun-brown or black-brown, often greenish or dun-green. The layer which originates the pseudopodia is very thick and inclosed in a thick jelly, often traversed by spaces through which the ray-like pseudopodia protrude. The Phæodella or peculiar pigment-granules of which the large Phæodium is composed, are, like the Phæodium, of varying form and size. Sometimes the Phæodium envelopes the greater part of the capsule, sometimes only one side of it. The extra-capsular yellow cells which are found in all typical Radiolaria are entirely wanted in the Phæodaria.

The siliceous skeleton is extra-capsular in all Phæodaria and is very peculiar in form and structure. Although the principal types of this group have corresponding representatives among the typical Radiolaria, they are usually easily distinguished from the latter. In a small division only, corresponding to the Thalassicollidæ, the siliceous skeleton is entirely wanting (Phævdinida). All other Phæodaria have a characteristic siliceous skeleton, according to the structure of which I distinguish in the group four orders and ten families.

Order I. PHÆOCYSTIA.-The siliceous skeleton is either entirely wanting or it consists of hollow spines, arranged sometimes irregularly, sometimes regularly, outside the central capsule.

Family I. PHEODINIDE.-Siliceous skeleton entirely wanting. Genera: Phæodina, Pheocolla.

Family 2. CANNORHAPHIDE.-The siliceous skeleton consists of numerous separate hollow spines, or portions of hollow network, which, scattered round the periphery of the extra-capsular soft substance, are usually arranged tangentially. Genera: Cannorhaphis, Thallassoplancta, Dictyocha.

Family 3. AULACANTHIDE.-The siliceous skeleton consists of hollow radial spines, which spring from the outer surface of the central capsule, and traverse the extracapsular jelly. The outer surface of the jelly is usually covered by a thick mantle of fine hollow siliceous needles, which are arranged tangentially and felted together. Genera: Aulacantha, Aulancora, Aulographium.

II. Order. PHEOGROMIA.-The siliceous skeleton consists of a single fenestrated shell which is of different forms, sometimes round, sometimes egg-shaped, often dipleuric, but always furnished with a large principal opening or mouth (more rarely with several openings). Hollow spines with peculiar pore-areas at their bases are often present.

Family 4. CHALLENGERIDE.-The siliceous skeleton consists of a fenestrated shell, uniaxial or dipleuric, often laterally compressed and carinated, often egg-shaped or oval, and furnished with a wide opening at one end of the axis. This mouth is seldom simple, it is usually armed with a hollow tooth, or with one or more, often branched hollow tubes. The fenestrated structure of the siliceous shell resembles most closely that of the diatoms; there is a fine pore in the middle of each of the hexagonal facets (Comp. Murray, 1876, .c., Pl. 24, Figs. 1, 2, 4). Genera:

Challengeria, Tuscarora, Gazelletta, Porcupinia, Entocanula, Lithogromia.

Family 5. CASTANELLIDE.-The siliceous skeleton consists of a simple round fenestrated shell, which has in one part of its upper surface a wide opening, often surrounded by peculiar processes. The fenestrated shell is usually ornamented with solid or hollow spines. Genera: Castanella, Castanidium, Castanissa, Castanopsis, Casta

nura.

Family 6. CIRCOPORIDÆ.—The siliceous skeleton consists of a sub-spherical or polyhedral siliceous shell, from which radiate in different directions hollow tubes (simple or branched, often provided with whorls of cilia). The shell has a large opening, as well as scattered porefacets. The pores usually form circles round the bases of the spines. the spines. (Comp. Murray, 1876, .c., Pl. 24, Fig. 5-6). Genera: Circoporus, Circospathis, Circostephanus, Porostephanus, Porospathis.

Order III. PHÆOSPHÆRIA.-The siliceous skeleton consists of numerous hollow tubes which are combined in a peculiar manner into a large, usually round or polyhedral fenestrated body.

Family 7. AULOSPHÆRIDÆ.-The siliceous shell is a fenestrated ball or a fenestrated polyhedral body whose lattice work is formed of hollow tubes. Hollow spines usually radiate from the points of connection of the latticework (Comp. Haeckel, "Monogr. der Radiol.," 1862, p. 357, Taf. x. xi.). Genera: Aulosphæra, Aulodictyum, Auloplegma.

Family 8. CANNOSPHÆRIDE.-The siliceous skeleton consists of a uniaxial globular or oval simple bounding shell, which is connected by means of hollow radial rods with a composite outer encrusting shell. The outer shell consists of hollow tubes, which form a wide-meshed latticed sphere; hollow simple or branched radial spines spring from the junctions of the lattice (Comp. Hertwig, .c., 1879, p. 91, Pl. ix.). Genera: Cannacantha, Cannosphæra, Calocantha.

Order IV. PHEOCONCHIA.-The siliceous skeleton consists of two separate fenestrated shells, like those of a bivalve mollusc. Simple or branched hollow tubes are often found at the junction of the valves.

Family 9. CONCHARIDE.-The siliceous skeleton consists of two semicircular or lenticular fenestrated shells turned each to each with the concavities inwards; the edges of the shells are usually set with rows of teeth, which lock together like the teeth of a bivalve (Comp. Murray, 1876, .c., Pl. 24, Fig. 3). Genera: Concharium, Conchopsis, Conchidium, Conchocaras.

Family 10. CÆLODENDRIDE.-The siliceous skeleton consists of two semicircular or lenticular fenestrated shells with the concave sides turned towards each other. Simple or tree-like branched hollow spines spring from the two opposite poles of the principal axis, or from the centre of the junction of the hemispheres. (Haeckel, "Monogr. d. Rad.," 1862, p. 360; Taf. xiii., Figs. 1-4; Taf. xxxii., Figs. 1-3.) Genera: Calodendrum, Calothamnus, Calodrymus, Calothauma.

Taking a comparative survey of the organisation of the known Phæodaria, we can define the characters of this group of Rhizopoda as follows:

The Phæodaria are single-celled Rhizopods, whose larger cell-body (the central-capsule) incloses a large nucleus (or inner-vesicle). The cell-membrane is always double, pierced by one or more large openings, through which the intra-capsular protoplasm communicates with the much more abundant extra-capsular protoplasm. In the latter, towards the outside, lies the phæodium, a peculiar thick mass of dark pigment-granules (or phaodella). The whole body is inclosed in a thick gelatinous covering, which is often provided with spaces which the numerous pseudopodia traverse in order to rediate freely beyond its outer surface. With very few exceptions (Phæodinidea) a well-developed, always extra-capsular

siliceous skeleton is secreted, which forms, as in the different groups of the typical Radiolaria, very varied and delicate structures, usually radiating outwards in hollow siliceous tubes. N. M.

NOTES

THE German Chemical Society in entering upon its thirteenth year has elected as president Prof. H. Kopp, of Heidelberg, who for some time past has devoted himself almost exclusively to the chronicling of the history of chemistry. At the same time Prof. Roscoe, of Manchester, and Prof. Marignac, of Geneva, who was compelled a year since by advanced age to relinquish active professorial duties, were elected to honorary membership. The Society now numbers 2,086, of whom 14 are honorary members and about 200 resident at Berlin. The Berichte of the Society, now certainly the most important chemical periodical of the day, forms for the past year a volume of over 2,550 pages containing over 600 communications. An exhaustive index of the first ten years is now in the press, and will soon be ready. The already bulky dimensions of the Berichte, with its constant yearly increase in size, have forced the council of the Society to propose an increase in the membership fee, which instead of 15s. shall be raised to 20s. annually. The fact that the Society can cover its ordinary expenses and send post free to its members in all parts of the world a periodical of the size above mentioned for so modest an annual fee, affords an interesting glimpse into the comparative cost of scientific association and activity in Germany and in our own country, where the expenses of membership in most of the scientific societies often exclude those in limited circumstances.

DR. JOSEPH LEIDY, Professor of Anatomy in the University of Pennsylvania, at Philadelphia, has just been awarded by the Council of the Society of Natural History, Boston, Mass., the great Walker prize, for the value of his researches in natural history. This prize is given once in five years, at the discretion of the Council, to the naturalist whom it shall decide to have performed the most elaborate and original work during that time. This prize has been awarded but once previously-five years ago -to Prof. Alexander Agassiz, of Cambridge. It is usually the sum of $500, but on account of the extraordinary merit of Dr. Leidy's researches the Council increased the sum to $1,000. Dr. Leidy was for a long time connected with the Geological Survey of the Territories, and one of his most important memoirs, vol. xii. of the final Reports, has just been issued by the Government. In collecting the materials for the volume, Dr. Leidy spent two seasons in the Western Territories under the auspices of the Survey.

THE following arrangements have just been made at the Royal Institution for the lectures after Easter. Tuesdays:-Prof. Huxley-Two Lectures on Dogs, and the Problems connected with them; Mr. Robert H. Scott, F.R.S.-Four Lectures on Wind and Weather; Mr. John Fiske-Three Lectures on American Political Ideas from the Standpoint of Universal History. Thursdays:-Prof. Tyndall-Six Lectures on Light as a Mode of Motion; Mr. T. W. Rhys Davids-Three Lectures on the Sacred Books of the Early Buddhists. Saturdays ::-Mr. James Sully-Three Lectures on Art and Vision; Prof. Henry Morley-Five Lectures on the Dramatists before Shakespeare, from the Origin of the English Drama, to the year of the Death of Marlowe (1593). The Friday Evening Meetings will be resumed on April 9-Prof. Huxley on the Coming of Age of the "Origin of Species." Succeeding discourses will probably be given by M. Ernest Renan, Mr. W. H. Pollock, Mr. W. Spottiswoode, Mr. G. J. Romanes, Lord Reay, Mr. H. H. Statham, and Mr. Francis Hueffer.

DR. C. W. SIEMENS was elected last month a Foreign Member of the Royal Academy of Sciences of Stockholm.

WE are glad to see that a movement has been set on foot for a testimonial to Dr. Farr as a mark of appreciation of the value of his statistical labours. The preliminary list of the committee is headed by the name of the Earl of Derby.

THE death is announced, on February 3, of Chintamanay Ragoonatha Charry, F. R.A.S., Head Assistant in the Madras Observatory for the last seventeen years. Attached to that institution for a period of over thirty-five years, he served in succession, in every grade, under the late Major W. S. Jacob, Col. W. K. Worster, Col. J. F. Tennant, R.E., and the present astronomer, and won the esteem and regard of each, by his intelligence, assiduity, and attachment to the pursuit he had adopted. His strict honesty and ready skill as an observer, combined with accuracy and speed in computation, and a fair and useful amount of self-acquired mathematical knowledge, rendered him, until disabled by impaired health, invaluable in the observatory; and the chief share in the Catalogue of Stars in hand, with the Transit Circle, since 1862, comprising already over 38,000 separate observations, is due to his personal exertions; besides many other special researches of a nature not often undertaken by ordinary assistants in observatories. He contributed several papers to the Royal Astronomical Society of London, and was elected a Fellow in January, 1872. He was twice successfully engaged in observations of total eclipses of the sun; on the first occasion in August, 1868, at Vunpurthy, in the Nizam's Dominions, in independent charge of a branch expedition for the purpose; and on the second, in December, 1871, at Avena hy, in the Coimbatore district. He was the first and only native of India who has yet entered the lists as a discoverer of new celestial objects, having detected two new variable stars, viz., R. Reticuli in 1867, and V. Cephei in 1878. He latterly took great interest in delivering public lectures on astronomy, with a view to enlighten his countrymen upon the subject, and to convince them of the absurdity of their notions in regard to celestial phenomena, by familiar explanations, in simple terms, of the true principles of the science, as opposed to the ignorant superstitions and rough predictions of Hindoo astrologers and empirics of the old school.

THE French papers, the Gardeners' Chronicle informs us, announce the death of Dr. Boisduval, to whose labours we owe one of the best treatises on the insects which affect garden plants. Dr. Boisduval was an ardent horticulturist, and a leading man for some time at the Central Horticultural Society of France. He died in his eighty-second year.

THE death is announced of Dr. Wilibald Artus, Professor of Philosophy at Jena, on February 7 last, aged seventy years. Also of Dr. Franz Xaver von Hlubek, Professor of Agriculture at the Graz Joanneum, on February 10, aged seventy-eight years. In the third week of February also died Herr Adolf Müller, one of the directors of the well-known Geographical Institute of Justus Perthes at Gotha.

A MONUMENT to Dr. August Petermann, the well-known geographer, has just been erected at Gotha. The design, which is very tasteful, is by Herr Eelbo, and the work was executed by the eminent sculptor, Herr Deutschmann.

A NUMBER of former pupils of Bernhard von Cotta propose to erect a monument in memory of the deceased geologist, and invite subscriptions for this purpose. The Royal Berg-Acadamie at Freiberg will receive contributions.

DURING Napoleon's rule the number of French astronomical observatories was increased to four, viz., Paris, Toulouse, Marseilles, and the Meudon Physical Observatory of Astronomy. The

present Government has created three new establishments— Lyons, Besançon, and Bordeaux, and M. Bischofsheim, the liberal banker, one at Nice. Among the high region meteorological observations Clermont-Ferrand could be used for astronomy if fitted with instruments and garrisoned by observers. The organisation of French astronomy has been completed by the creation of a school of astronomy at the Paris Observatory by Admiral Mouchez, who had already organised a school of astronomy for navy officers at Montsouris. The course of studies, whose duration is two years, was recently opened; the first year will be occupied in learning exclusively the meridian service, and the second the equatorial service, as well as general physics. The experiments connected with the physical department will take place at the Sorbonne, in the laboratories, as well as at the observatory. Four pupils have been selected by the director for the first promotion. They will have a salary of 1,800 francs a year, with lodgings in the buildings of the Observatory. After having successfully passed their examinations, they will be appointed assistant-astronomers in one of the government observatories. By a singular exception to the rules of the competition principles they are not appointed after an examination, but selected by the director of the public observatory from the Normal School, Polytechnic School, and Licenciéses-Sciences mathématiques. They must not be more than twenty-five years of age when nominated. In addition to the Government pupils two more are trained at the expense of M. Bischofsheim, for his Nice observatory, and three others have been authorised to follow the course of lectures and applications after having proved their ability. Similar authorisations may be granted every year on application. Meridian service will be taught by Admiral Mouchez, M. Loewy, M. Perigaud, astronomer, and M. Gaillot, head of the Bureau des Calculs.

THE American Academy of Arts and Sciences intends to celebrate its 100th anniversary on May 26.

THE Easter Monday and Tuesday excursion of the Geologists' Association will be to South Hampshire, with Christchurch as a

centre.

THE following statistics in connection with the termination of the St. Gothard tunnel will be of interest to our readers :-The total length of the tunnel is 14,920 metres, or 112 feet more than 9 miles. Its width is 63 metres, or 21 feet. The undertaking has required for its execution seven years and five months-four and a half years less than the time taken to complete the Mont Cenis tunnel. The average daily progress was 5 metres or 18 feet. The number of holes bored amounted to 320,000, and 490,000 kilogrammes of dynamite were used in blasting. 1,650,000 drills were consumed and 1,450,000 cartloads of débris were taken out from the bowels of the mountain.

violent earthquake occurred on February 9 at Kaposvar and other localities of the Somogy County (Hungary) shortly before midnight. A moderate shock of earthquake, proceeding in the direction from south to north, was felt in Lower Carniola in several places, such as Gradaz and Rudolfswerth, on February 12, at 5.15 p.m.

A FEW days since the Bulletin of the French Bureau Central of

Meteorology published for the first time the daily telegrams sent from Briançon meteorological observatory, whose altitude is 1,300 metres, 300 more than the summit of Puy de Dôme. At present the French high region stations are three in number,

Briançon, Puy de Dôme, and Pic du Midi. A fourth is being fitted on the new German frontier, which will complete the system.

DR. KIENITZ-GERLOFF, of Weilberg, writes to inform botanists that henceforth he is charged, in place of Herr Limpricht, with the account of bryology for the Botanische Jahresbericht, edited by Herr Just. He begs bryologists to favour him by transmitting their papers.

IN connection with the Commission which has been organised in Switzerland for the investigation of earthquakes, to which we referred in a recent article, Prof. Heim, of Zurich, publishes a little brochure, on "Les Tremblements de Terre et leur Étude scientifique," in which he reviews existing facts and theories, gives instructions for the observation of earthquakes, and describes the organisation of the Swiss Commission.

No. 3 of the Proceedings of the Birmingham Philosophical Society contains a number of papers of considerable interest. Dr. Richard Norris has an elaborate contribution, illustrated with many photographs, "On the Existence in Mammalian Blood of a New Morphological Element which explains the Origin of the Red Disk and the Formation of Fibrine"; Mr. of Plants; and Prof. Bonney contributes a paper on the preLawson Tait describes the researches on the Digestive Principles

Cambrian Rocks of Great Britain.

THE following papers were read yesterday at the half-yearly general meeting of the Scottish Meteorological Society :-1. Report from the Council of the Society. 2. The Velocity of the Wind at different Heights above the Ground, by Thomas Stevenson, Honorary Secretary. 3. The Storm of December 28, 1879, by Alexander Buchan, Secretary. 4. The Influence of the recent Fog on the Health of London, by Dr. Arthur Mitchell. 5. Thunderstorms in Scotland, their Diurnal Periods, by Alexander Buchan.

THE additions to the Zoological Society's Gardens during the past week include a Macaque Monkey (Macacus cynomolgus)

RADICAL remedies are now being adopted in France with a view of exterminating the phylloxera. The Government proposes to spend the sum of 2,400,000 francs (96,000/.) for inundating 7,000 hectares of vineyards in the Departments L'Aude and L'Hérault.

THE earthquakes in San Salvador, viz., in the capital and the cities in the vicinity of Lake Ilopango, seem to have lasted from December 21 until January 10. A violent shock on December 27 destroyed a number of villages near Lakes Ilopango and Zollapango, some fifteen miles from the capital. A violent shock was again felt on January 1, particularly in the port of La Libertad. The city of San Salvador is stated to be quite deserted by the population. News dated February 5 report earthquakes from Cuba and from various parts of Mexico, particularly from the districts of Cordoba, Orizaba, Tehuacan, and Veracruz. A

Monkey (Cercopithecus cynosurus) from West Africa, presented by Lady Dorothy Nevill; two Wild Boars (Sus scrofa) from India, presented by H.R. H. the Prince of Wales, K.G.; a Craleating Opossum (Didelphys cancrivora) from St. Vincent, W.I., presented by Mr. Geo. Dundas; a Leadbeater's Cockatoo (Cacatua leadbeateri) from Australia, presented by Mr. J. Veale ; a Greater Sulphur-crested Cockatoo (Cacatua galerita) from Australia, presented by Mr. T. Phillips; a Herring Gull (Larus argentatus), European, presented by Mr. H. D. Martin; a Macaque Monkey (Macacus cynomolgus) from India, a Crabeating Raccoon (Procyon cancrivorus) from Baranquilla, two Wild Cats (Felis catus) from Spain, a Ring-tailed Coati (Nasua rufa), a Harpy Eagle (Thrasaëtus harpyia) from South America, deposited; a Harnessed Antelope (Tragelaphus scriptus) from West Africa, purchased; a Red Kangaroo (Macropus rujus), a Gaimard's Rat-Kangaroo (Hypsiprymnus gaimardi), born in the Gardens.

OUR ASTRONOMICAL COLUMN

AN ASTRONOMICAL BIBLIOGRAPHY.-We are somewhat late in drawing attention to a prospectus of what must prove a very important work in astronomical literature, if it is carried out with the care and completeness of which there is every promise. MM. Houzeau and Lancaster, respectively the director and librarian of the Royal Observatory, Brussels, have projected a "Bibliographie générale de l'Astronomie, ou Catalogue méthodique des Ouvrages, des Mémoires et des Observations astronomiques publiés depuis l'Origine de l'Imprimerie jusqu'en 1880," and it is clear from the particulars furnished in the prospectus that the design has been thoroughly considered and formulated.

It is intended to divide the work into three sections :-(I.) Ouvrages or separate publications; (II.) Memoirs; (III.) Observations. For the first section there are available the astronomical bibliographies of Weidler, Scheibel, and Lalande referring to what may be termed the ancient period. For the modern the authors have made use of the catalogue (1860) of the splendid astronomical library of the Imperial Observatory of Pulkowa, and the catalogues of other observatories; more than a thousand journals and catalogues of different countries have been consulted for this division of the work. A list of the principal astronomical manuscripts, not yet published, which are found in the inventories of the various European libraries is added. Bibliographical notes, as, for instance, notes upon changes made in successive editions of a work are also appended, as well as a kind of analysis of works of an encyclopaedic character. An alphabetical table of the authors and a methodical table of analysed matters accom. panies this part of the work.

The second section, as forming a more immediate desideratum, it is intended shall be the first published, and the first fasciculus was about to be placed in the printer's hands, when the prospectus was issued, the others to follow rapidly. All the collections where astronomy could enter were consulted for this division, either directly or through the catalogue of scientific papers issued by the Royal Society or the Repertorium Commentationum of Reuss; it is mentioned that recourse has been had to the publications of nearly three hundred scientific societies, and more than a hundred and sixty reviews or journals. The authors have exercised great care in the classification of the contents, and in attributing each memoir to the sub-section to which it appertains; the collection where each memoir is found is inaicated by a system of abbreviations. An alphabetical table of authors, briefly noting their different works for more ready reference, accompanies this second part also. In this division astronomical physics are included,

In the Section III., Observations, it has been proposed to arrange a kind of general table of observations, nearly upon the plan of the indexes to the Astronomische Nachrichten, but rather taking for a model the Repertorium der Cometen-Astronomie of Carl. In this section are mentioned the sources for observations of spots, faculæ, and protuberances of the sun, in chronological order from their respective discovery, observations of solar and lunar eclipses, each separately, monographs of the asteroids, bibliographical monographs of the comets, star catalogues, calculations relating to the compound stars, and individual descriptions of the variable stars and nebulæ. The authors claim to have analysed the publications of the different observatories with the most scrupulous attention in order to render this part of their work as complete and as useful as possible.

The entire work will form three large octavo volumes in double column, which will appear by fascicules of 300 to 400 pages; specimens of the form of execution of the three divisions of this laborious work are attached to the prospectus. It appears to be intended to issue it in sheets of sixteen pages, or thirty-two columns, at the price of three pence per sheet, payment to be made for each fascicule.

Every astronomer and astronomical student will applaud the zeal evinced by MM. Houzeau and Lancaster in undertaking to provide so valuable an addition to the literature of the science, and will cordially wish them success in every way in their selfimposed labours.

THE GREAT SOUTHERN COMET.-A private letter from Mr. Gill, H.M. Astronomer at the Cape, furnishes some particulars of his observations of the great comet up to the evening of the 9th ult. Table Mountain interfering at first with the view from the Royal Observatory, Mr. Gill proceeded to Seapoint, on the west side of the mountain, where, from the garden of Mr. H.

Solomon, in which Sir Thomas Maclear observed Donati's comet in 1858, he sketched the position of the tail amongst the stars on several evenings before the nucleus had withdrawn sufficiently from the sun's place to be visible. The nucleus was first seen on February 8, and then only for a few minutes through cloud; Mr. Gill thought it might have been visible the preceding evening, but haze near the sea horizon rendered it very difficult to say where the tail ended. He describes it as a very poor affair, a faint nebulous thing not at all worthy of so fine a tail." Attempts were made to fix its position at the Royal Observatory on February 9, but only a glimpse with an opera-glass through cloud was obtained. The nucleus was "6 a little N. and E. of Sculptoris;" in a tracing accompanying the letter in question, however, the nucleus is shown a little south and east of the star, and midway between two stars, which from Gould's "Uranometria Argentina," appear to be Lacaille 6 and 34, so that the place referred to the epoch of the "Uranometria," 18750 would be in about right ascension 2° 20′ with 37° 50′ south declination, which is far from the position given by the elements telegraphed from Rio de Janeiro (to which reference was made last week) whether the heliocentric motion be assumed direct or retrograde; probably the orbit has been vitiated in transmission. On February 6 the tail appears to have been traceable nearly to Canopus.

BIOLOGICAL NOTES

ON CERTAIN REMARKABLE PHENOMENA PRESENTED BY the Coloured Blood-CorpuSCLES OF THE FROG.-Repeated observations tend to show that the structure of the coloured bloodcorpuscle is by no means so simple as is usually assumed: and from this point of view the observations made by J. Gaule in Prof. Ludwig's laboratory at Leipzig (Archiv für Physiologie, v. Du BoisReymond, 1880) are of singular interest. On diluting the fresh blood from a vigorous frog with o'6 salt solution, and exposing it after rapid defibrination to a temperature of 32°-36° C. on the hot stage of the microscope, the escape of a peculiar body may be observed in many of the corpuscles. The bodies thus evolved simulate worms so closely by their form and wriggling movements, that Gaule styles them "Würmchen," which may be translated vermicles. However, he concludes from several reasons that they are simply protoplasmic portions of the corpuscles, which, under these special conditions, separate for a short independent life. He makes no reference to previous workers in the same field; but it would seem not improbable that his "Würmchen" correspond with the maculæ, which Prof. Roberts of Manchester revealed seventeen years ago by treating the corpuscles with tannin or magenta, reagents which would of course prevent any further signs of life in the objects. The "vermicles are about half the length of the red corpuscle, pointed at either end, but more in front, and containing one or two vesicles or droplets. Their singular movements deserve a rather full description. After wriggling out of the corpuscle, in which it makes its appearance as a rod-like body beside the nucleus, the "vermicle" moves on, trailing the corpuscle behind by a long thread. On meeting a second corpuscle it bores into it, withdraws, pushes it aside, and goes on carrying this too in its train; and though the threads finally give way, "vermicles" may be seen dragging three, four, or more corpuscles after them. The corpuscles, quitted or attacked in this way, undergo in a short time changes of form and colour leading to complete disorganisation, which otherwise, under similar conditions, require hours for their accomplishment. Finally the "vermicle" also undergoes disorganisation. While the conditions given above are found on the whole most successful in bringing about these results. Gaule indicates limits of temperature and dilution within which they often occur, usually with slight modifications. It is this variation with the conditions of the experiment that supplies one of his strongest arguments against the previous individual existence of these bodies.

THE HUMAN RETINA.-In a recent note to the Vienna Academy Herr Salzer offers an estimate (based on numeration) of the probable number of optic nerve-fibres and of retinal cones in a human eye. The number of the former he supposes to be about 438,000, that of the latter 3,360,000. This gives seven or eight cones for each nerve-fibre, supposing all fibres of the optic nerve to be connected with cones, and equally distributed among them.