New Species of Bulbochate.*-O. Nordstedt describes two new species of this genus. The first, from Brazil, was sterile; but is distinguished from all known species by a whorl of spines in the middle of each cell except the basal and all the hair-cells. The other species is from Australia, where it grows attached to Characes. It is allied to B. minor, but is characterized by peculiar dwarf males. terminal cells of these dwarf males bear a bristle; and the antheridium is also sometimes divided into two branches. It constitutes therefore an intermediate form between those with unbranched dwarf males destitute of bristle, and the ordinary large branched, bristle-bearing plants, the antheridium of which is never branched. The New Genus of Oscillarieæ.t-Under the name Borzia trilocularis F. Cohn describes a new oscillarian alga exhibiting a structure altogether parallel to Bacterium. It forms olive-brown masses in fresh water inhabited by Edogonium and other algae. It consists of short oblong rods which oscillate slowly and with difficulty, each composed of three cells filled with granular phycochrome, the two terminal cells being rounded off. By cell-division the number of cells increases to six, and each rod then divides into two. In the neighbourhood of Breslau it shows no disposition to assume a filamentous or any other condition. Vaucheria of Montevideo.-J. Arechavaleta has studied the species of Vaucheria found near Montevideo, of which he gives a detailed description, with diagnosis of eight new species. Some of these appear, however, to be identical with well-known European species; and of others the description given is deficient in some points necessary to determine whether they must be regarded as good species. Gongrosira.§-N. Wille, who has found Gongrosira de Baryana Rab., growing on Planorbis and Paludina, has proved, by cultivation, that it is a form of Trentepohlia Mart. (Chroolepus Ag.). The braching resembles at first that of Coleochate irregularis or Trentepohlia umbrina, forming a disk of cells from which the branches rise. In each cell is only one nucleus; the chlorophyll is parietal; sometimes a few drops of oil occur in the centre of the cell. The cell-wall is thick and evidently laminated, and readily becomes mucilaginous. Swarm-spores are formed in terminal sporangia, resembling those of Trentepohlia. No conjugation was observed, nor was the further development of the spores followed out. Propagation takes place by single cells becoming detached from the vertical branches, and developing directly into new plants. The organs described by Rabenhorst as oogonia the author believes *SB. Phytograph. Gesell. Lund., May 28, 1883. See Bot. Centralbl., xvi. (1883) p. 95. † JB. Schles. Gesell. Vaterl. Cult., 1883, pp. 226-7. p. 627. Anal. Aten. del Uruguay, iv. (1883) p. 18 (2 pls.). See Bot. Ztg., xli. (1883) § Ofvers. K. Svensk. Vetensk. Akad. Förhandl., 1883, pp. 5-20 (1 pl.). See Bot. Centralbl., xvi. (1883) p. 162. to be resting-cells similar to those of Conferva pachyderma. The immotile reproductive cells, which are formed directly without any true process of cell-formation, he calls "akinetes "; while to those formed asexually by true cell-formation he gives the term "aplanospores"; they germinate directly, or after a period of rest. Under cultivation Trentepohlia umbrina may become quite green. Other species of the pseudo-genus Gongrosira, Wille refers as conditions of species belonging to different genera as follows:G. dichotoma Kütz., is a peculiar aplanospore condition of Vaucheria geminata Walz.; G. clavata Kütz. is the sporiferous vegetative plant of Botrydium granulatum; G. ericetorum Kütz. is the protonema of a moss; G. ericetorum v. subsimplex Rab. is probably a Ulothrix or Conferva; G. pygmaea probably a Stigeoclonium; G. Sclerococcus Kütz. (Stereococcus viridis Kütz.) may be a Trentepohlia; G. protogenita Kütz. is probably the palmella-form of a Stigeoclonium; Reinsch's species cannot be determined; G. onusta Zell. comes near Trentepohlia de Baryana. Phyllosiphon Arisari.-M. Franke finds this parasitic alga abundantly on the leaves of Arisarum vulgare in the neighbourhood of Messina, and elsewhere in Sicily and Calabria; but it appears never to attack A. italicum. The spores are capable of germinating at any period of the year, but must go through a period of rest; the larger spores appear to divide into several. They always attack their host by penetrating the epidermis between two cells, which they force apart by their germinating filament. The restricted conditions necessary for the germination of the spores greatly diminish its destructive effects. Occurrence of Crystals of Gypsum in the Desmidieæ. The occurrence of crystals of calcium sulphate, endowed with a peculiar "dancing" motion, has long been known in the terminal vesicles of Closterium and in other desmids; the phenomenon has now been carefully investigated by A. Fischer. Their chemical constitution was clearly established by different tests. They are always quite isolated from one another, and occur in all parts of the cells, though in the greatest quantity in the terminal vesicles; they are either carried along passively by the currents of protoplasm, or they "swarm" in the space filled with cell-sap between the cell-wall and the radiating chlorophyll-bodies; these vesicles are not true vacuoles, but portions of the cell-sap space. The crystals are not formed, nor do they grow, in this vesicle, but reach it in a mature condition from some other part of the cell, being formed apparently in the furrows between the bands of the chlorophyll-bodies; from here they are carried to the terminal chambers by the protoplasmic currents. Fischer found these crystals in all the species of Closterium which he examined; also in various species of Cosmarium (though individuals are often entirely destitute of them), their form being the same as in Closterium. They occur also in Micrasterias, Euastrum, in which JB. Schles. Gesell. Vaterl. Cult., 1883, pp. 195-7. Cf. this Journal, ii. (1879) p. 606; ii. (1882) p. 391; iii. (1883) p. 108. + Pringsheim's Jahrb. f. Wiss. Bot., xiv. (1883) pp. 133-84 (2 pls.). genera also they are not invariably present, and always in Pleurotanium, Penium, and Tetmemorus, but were absent from all the specimens examined of Staurastrum, Desmidium, and Hyalotheca. They appear to be entirely confined to the Desmidieæ, other fresh-water algae containing calcium oxalate, especially species of Spirogyra, but not calcium sulphate. The absence of crystals of calcium sulphate, either occasionally or regularly, does not, in the opinion of the author, imply the absence of the salt; since, from its solubility in water, it may be present in the cell-sap. The zygospores of Closterium were always found to contain crystals. Calcium sulphate is an excretory product in the process of metastasis, corresponding to the production of calcium oxalate in the higher plants; and the quantity excreted determines whether it shall remain entirely dissolved in the cell-sap, or whether a portion of it shall separate in the form of crystals. MICROSCOPY. a. Instruments, Accessories, &c. "Giant Electric Microscope."-One of the attractions at the Crystal Palace is what is advertised as "Les Invisibles in the Giant Electric Microscope." We take the following description from a daily paper,* no other description being forthcoming. "A number of gentlemen assembled at the exhibition court of the Crystal Palace on Saturday, by invitation of the directors, to witness the first representation in England of Les Invisibles,' an exhibition of natural objects magnified and displayed by means of the great electric Microscope. The apparatus used in the exhibition is the invention of Messrs. Bauer and Co., and Les Invisibles' has quite recently attracted a good many visitors to the old Comédie Parisienne, where, as well as at the Athenæum at Nice, a series of representations has been given. The invention may be described in a few words as being the application of electric light to the Microscope, and the result, so far as the spectacle is concerned, is a sort of improved and enlarged magic lantern. Every one is familiar with the former exhibitions at the Polytechnic and elsewhere of the animalcula (sic) in a drop of water, magnified and thrown, by the aid of the lime-light, on to a white screen. Precisely the same sort of effect was produced on Saturday by Mr. F. Link, the London agent for Messrs. Bauer and Co., with this difference, that the magnifying power was enormously in excess of that attained in the old magic lantern entertainments. The electric Microscope has, in fact, made it possible to exhibit in a most attractive form, the appearances presented by minute natural objects when placed under the most powerful magnifying glass. Indeed, the difficulty with which Mr. Link had to contend on *Morning Post,' 5th Jan., 1884. Saturday was the smallness of the screen upon which his pictures were thrown. For instance, only a small section of a butterfly's wing could be shown at a time, although the screen was as large as the size of the entertainment court would permit, whilst the living organisms in a spot of water and the mites in a small piece of cheese were enlarged until they presented a perfectly appalling spectacle to a timid mind. The capabilities of the apparatus may be imagined from the fact that the eye of a fly was presented in a form no less than four million times its natural size. The electric Microscope, which is worked by an ordinary primary battery, may be said to have extended almost indefinitely the possibilities of presenting in an attractive and instructive manner the wonderful facts of natural science." Aylward's Rotating and Swinging Tail-piece Microscope.-Mr. H. P. Aylward has added a new movement to the radial swinging tail-piece. Not only do the mirror and the substage swing on separate tail-pieces, either above or below the stage, but they can also be rotated completely round the stage, so that the direction of the illumination in azimuth can be more readily varied than is the case with Zentmayer's form of tail-piece. The stage consists of a fixed ring attached to the limb by an angle-plate of brass; this ring carries above it the rotating objectstage, and beneath a rotating collar is fitted, which has a shoulder attachment at right angles carrying the two tail-pieces on an axis slightly above the plane of the object-stage, and allowing of their rotation round the optic axis. The angle-plate, by which the stagering is fixed to the limb, is so arranged that the shoulder carrying the tail-pieces will pass behind it, and there is therefore no obstruction to complete rotation. This plan of suspending the tail-pieces is far more convenient than that devised by L. Jaubert, or that of J. Mackenzie.† * McLaren's Microscope with Rotating Foot.-Mr. A. McLaren has devised a simple plan of giving greater stability to Microscopes mounted on a pillar support on a horse-shoe foot, which are very liable to be overturned when much inclined from the perpendicular. The plan consists in making the foot rotate at its junction (fig. 9, A) * See this Journal, i. (1881) pp. 514-5. |