Among other novelties introduced by Stein are the following: The genus Cenchridium Ehrbg., hitherto placed with the Foraminifera and forming Williamson's Entosolenia, is referred to the Prorocentrinæ from its similarity to Dinopyxis, and particularly D. compressa. Examination of living individuals is desirable before this classification can be accepted. Dinopyxis compressa has hitherto been, Stein thinks, erroneously classed as a diatom (= Pyxidicola compressa Baily, P. prisca Ehrbg. ?). The problematical organisms which Ehrenberg obtained from flints and described as species of Xanthidium (distinct from the true species of Xanthidium, which are unicellular algae of fresh water) Stein places in the genus Cladopyxis the sole genus of the Cladopyxide-on account of peculiarities of form which he considers show them to belong to the Flagellata. A species of Cladopyxis from the stomach of a Salpa is evidently very nearly allied to X. ramosum and X. furcatum Ehrbg. Cilio-Flagellata.*-G. Pouchet has made some observations on Cilio-flagellates, supplementing those of Bergh.† A number of new forms are described, most of which the author hesitates to designate as new species on account of the very rudimentary state of our knowledge, ranging them as varieties in "specific groups.' Of Protoperidinium two new species are described, of Peridinium one, Glenodinium three, and Gymnodinium one. No new light (the author says) is thrown on the mode of evolution and reproduction, and the facts observed in regard to the conjugation of Ceratium, the gemination of Dinophysis, and the segmentation of Amphidinium " do not seem to agree precisely with one another, and would suggest very great differences in the group which seems, however, to be so homogeneous and so natural." Some species may present themselves in chains which break up to set at liberty the individuals which have arrived at their full development. The origin of these chains remains completely unknown. It seems scarcely probable that they are formed by epigenesis. They seem rather to result from the simultaneous development of a certain number of cells originally conjugated. Other Cilio-flagellates (Dinophysis) are found in groups of two individuals, which are destined to separate later on; others (Amphidinium) divide and multiply after the manner of diatoms. The mucous cyst, observed by Stein and Bergh, within which fission is said to take place, was never seen, but in some Cilio-flagellates provided with a test (Peridinium divergens) the body retracted within it was seen to give rise by fission to two new individuals. The Cilio-flagellates appear to be directly allied to the Noctiluca, which latter are perhaps directly derived from P. divergens. "Everything indicates the closest relationship between these organisms, and if the evolutionary chains pointed out here should come to be directly demonstrated, or if, on the other hand, the peridinian chains should Journ. Anat. et Physiol., xix. (1883) pp. 399-455 (12 figs. and 4 pls.). + Cf. this Journal, ii. (1882) p. 351. arise, as there is every reason to believe, from cellular chains closely related to alga (just as Amphidinium with the diatoms) then these peculiarities added to the organic complication of the genus Polykrikos furnished with an integument and nematocysts, would contribute to render still more indistinct the otherwise entirely artificial line between Plants and Animals." New Choano-Flagellata.*-A. C. Stokes describes some new species of W. Saville Kent's order of Choano-Flagellata, viz. Monosiga robusta, M. Woodie, M. longipes, Codosiga dichotoma, C. longipes, Salpingoca acuminata. Anatomy of Sticholonche zanclea.t-H. Fol gives a detailed account of the anatomy of this Protozoon, which was originally discovered and shortly described by R. Hertwig. He regards it as forming a special order of Rhizopods - Taxopoda. The main features of its organization are as follows:-The oval body is covered externally by a firm envelope, to which are attached a number of hollow spicules, probably chitinous, with a slight deposition of calcareous salts; these are arranged in radiately disposed groups; the membrane itself appears to be permeated by a system of fine tubules. The body is composed of a fine granular substance in which are imbedded a vast number of clear spherical globules; in the interior is a large "reniform body," covered with a closely set array of rods, and containing in its interior a spherical highly refracting body. There are no true pseudopodia, but a series of "arms," somewhat like the suckers of Acineto, attached in four longitudinal rows to the rods of the reniform body. Thus far the ohservations are mainly confirmatory of those of Hertwig. The most important addition to the anatomy of this protozoon is the description of a large mass situated on the concave surface of the reniform body. This mass shows two distinct forms, always seen in different individuals, (1) a number of small globules which pass gradually into the sarcode globules of the body, (2) a single large corpuscle increasing in size with the growth of the animal, and which, when it has arrived at complete maturity, is liberated in the form of an holotrichous Infusorian. This body was observed and figured by Hertwig in certain Radiolarians but erroneously described as a nucleus, and since the "nucleus" is inclosed within the central capsule in these Radiolarians, it seems to be proved that the latter cannot correspond to the reniform body of Sticholonche. The further development of this infusoriform body was watched, and it appeared finally to break up into a number of minute spores, the subsequent fate of which could not be traced. The hypothesis at once suggests itself that the two kinds of individuals, one with the mass of globules, the other with the infusoriform body, are of different sexes, but all attempts at fertilization failed. Nothing therefore can be said with certainty concerning the relations and functions of these different structures, though it is evident that the latter at any rate are connected with * Amer. Mon. Micr. Journ., iv. (1883) pp. 204-8 (6 figs.). the reproductive process; if merely parasites their constant presence and in the same spot is inexplicable. A comparison with other Rhizopods affords no satisfactory explanation of the problematical infusoriform body, though it possibly corresponds to the gemmules arising within the central capsule by which many Radiolarians are propagated. The following is M. Fol's diagnosis of this genus "Pseudopodia in four rows. Nucleiform body curved in the form of a bean. Membranous envelope of intercrossed tubular fibres. Spines in the form of pins and sabres, arranged in divergent groups." Studies on the Foraminifera.*-G. Shacko has studied some Orbulinæ from Cape Verde, in which he noticed the large spheres which Moseley regarded as parasitic algae, and Lankester as cellnuclei; he is himself inclined to regard them as embryonic chambers, but he did not test them with acids. In some Orbulinæ from the miocene strata of Lapugy he found the shells closely covered by Globigerinæ, but he is not able to understand exactly what their relations to one another were. A study of the embryos of Peneroplis proteus leads him to think that there must be here a very regular constriction of the protoplasm with the formation of nuclei, or else a very regular breaking-up of the whole of the sarcode, such as is seen in the central capsule of the Radiolaria. The perforation of the shell of Peneroplis has also been studied, and the impression arrived at is that the upper layer of the shell was at first really perforated, and that later on this perforation disappeared, when the septal surfaces and their large tubes became firmer. Development of Stylorhynchus.+-A. Schneider finds that Stylorhynchus passes through the greater number of its developmental stages, and often even acquires its adult structure in the interior of an epithelial cell of its host. The same epithelial cell contains several developing parasites. The young is at first similar to a coccidium; this coccidium buds off the segment which will answer to the deutomerite of the adult, then the protomerite, and finally the neck. The primitive body, therefore, minus the nucleus, corresponds to the fixation apparatus of the adult. The nucleus retains its original position till the formation of the protomerite, when it descends into the deutomerite; and the cavity of the rostrum corresponds to the position originally occupied by the nucleus. *Arch. f. Naturgesch., xlix. (1883) pp. 428-53 (2 pls.). BOTANY. A. GENERAL, including Embryology and Histology Relations of Protoplasm and Cell-wall in the Vegetable Cell.*— F. O. Bower considers that it has now been demonstrated with as much certainty as is possible, by the use of microchemical and staining reagents, that in certain cases, the number of which is now constantly being increased, there is a direct connection between the protoplasmic bodies on opposite sides of cell-walls, and that this connection is established by means of fine strings of protoplasm which, in the cases observed, run nearly transversely through the walls. The question remains whether this is the only mode of permeation of the cell-wall by protoplasm. The author cannot accept it as proved as yet that any further permeation of the cell-wall by protoplasm really exists, but he brings forward certain grounds for regarding such a permeation as possible or even probable, taking into account chiefly those phenomena observed in free cell-walls, in order thereby to avoid any confusion with connecting strings, such as those already proved to exist: 1. The strings already observed vary greatly in thickness, from the well-marked to the undistinguishable; thus we have evidence of the existence of strings which would probably not have been recognized were it not for comparison with other examples. Further, it has been shown, in the author's paper on plasmolysis, that protoplasm may be drawn out into strings so fine as to defy definition, even by high powers of the Microscope; thus there can be no objection on the ground of the small size of the hypothetical strings or reticulum. 2. Those cases in which a perforation of cell-walls has been demonstrated are those very cases in which a most efficient physiological connection is required. There is no reason why a less obvious permeation should be denied where the requirements are less, but by no means absent. 3. There is a priori probability of some form of permeation of cell-wall by protoplasm, if Strasburger's account of the growth of cell-walls be correct. 4. A strong argument in favour of such general permeation of walls by protoplasm is found in the existence of important chemical changes in the substance of certain cell-walls at points at a considerable distance from the main protoplasmic body, e. g. formation of cuticular substance, wax, &c., which differ fundamentally from cellulose, are insoluble in water, and are apparently formed in the wall itself. The tendency of recent observations is to show more and more clearly how close the connection of protoplasm with the important chemical changes in the plant is; thus it appears probable that protoplasm is present in some form or other in the cell-wall. * Proc. Brit. Assoc. Adv. Sci., 1883, p. 581. Cf. this Journal, iii. (1883) pp. 225, 524, 677. Reasons are also given for thinking that the exposure to air is not an important factor in the above changes. These and other con siderations show that though this permeation of the wall cannot be accepted as proved as yet in any one case, still the subject deserves more close attention than it has yet received, while it may be expected that the application of new methods may produce definite results bearing on this very important question. Intercellular Connection of Protoplasts.-W. Hillhouse gives the results of a large number of observations to prove the intercellular connection of protoplasm. Out of twenty-two plants examined, these connections were only found in the cortical tissue of Ilex Aquifolium and Esculus hippocastanum, the pulvinus of Prunus laurocerasus, and the winter bud pith of Acer pseudoplatanus; he, however, points out that these connections are easily broken in preparation, and that a single connection between a number of cells would be sufficient to produce a perfect unity of action. His conclusions are: 1. That protoplasmic threads connecting neighbouring protoplasts are present in such widely different and diffused structures as sievetubes, cortical parenchyma, leaf-pulvinus, pith of resting leaf-bud, and endosperm of seeds. 2. That in the contraction of the protoplast in natural plasmolysis these threads would normally remain unbroken. 3. That they may serve to transmit impulses from one cell to another, acting in this way somewhat like a nervous system. 4. That besides the perforating threads, equally widely spread and much more numerous, are threads which attach the protoplast to the cell-wall, whether at the base of pits or otherwise, and that these threads are often opposite each other. 5. That the closing membrane separating two threads often shows differentiation, which suggests permeability, if not " sieve-perforation." 6. That in the contraction of the protoplast in natural plasmolysis these threads would naturally be unbroken. 7. That these threads may, when in extension, act upon the cellwall and put it in a state of slight positive tension. 8. That the presence of minute perforations communicating from cavity to cavity of living cells would not, and when communicating with the intercellular spaces need not, be a hindrance to the turgidity of the cells. Polyembryony of Trifolium pratense.†-B. Jönsson describes a case of polyembryony in the common red clover. He regards it as arising, not from the presence of several embryo-sacs, but from the formation of more than one ovum-cell in the embryo-sac. Mechanical Structure of Pollen-grains.-J. Vesque states that pollen-grains shrink from evaporation of water; those of a spherical *Proc. Brit. Assoc. Adv. Sci., 1883. Cf. Nature, xxix. (1883) p. 582. Cf. this Journal, iii. (1883) p. 524. + Bot. Notiser, 1883, pp. 135-7. See Bot. Centralbl., xvi. (1883) p. 171. Comptes Rendus, xcvi. (1883) pp. 1684–6. |