Abstract
London. Royal Society, June 15.—Sir Charles Sherrington, president, in the chair.—H. M. Evans: The defensive spines of fishes, living and fossil, and the glandular construction in connexion therewith, and observations on the nature of fish venoms. The gland in the groove of the spine of the sting-ray (Trygon pastinaca) consists of two portions—the deepest part of the groove contains an alveolar-connective tissue structure, which is separated from the true glandular epithelium by a pigmented capillary layer. The dorsal fin-spines of the spiny dog-fish Acanthias are grooved, and the groove is occupied by a gland with definite follicles. Cestracion also has a well-developed gland at the base of the dorsal fin spines. The spines of Chimasra and of the Pleuracanthidæ show structures which suggest a specialised function. The nature and properties of Weever venom are described; the filtration of venom profoundly affects its hæmolytic properties. Experiments are described on the native use of abrin as an antidote to fish venoms.—D. W. Cutler, L. M. Crump, and H. Sandon: A quantitative investigation of the bacterial and protozoan population of the soil: with an account of the protozoan fauna. The results of 365 consecutive daily counts of the numbers of bacteria and of six species of protozoa in a natural field soil are given. Large fluctuations occur which cannot be correlated with meteorological conditions. Fourteen-day averages of the daily numbers show marked seasonal changes superimposed on the daily variations in numbers. In general, both bacteria and protozoa are most abundant at the end of November, and fewest during February. The changes are not directly influenced by temperature or rainfall. An inverse relationship is found between the numbers of bacteria and certain amœbæ, and a two-day periodicity obtains for the numbers of the flagellate Oicomonas termo which are active.—D. W. Devanesen: The development of the calcareous parts of the lantern of Aristotle in Echinus miliaris. All the calcareous elements of the lantern of Aristotle, with the exception of the teeth, are deposited as triradiate spicules. A “compass” arises from two rudimentary spicules. It is the only element of the lantern absent in the “echinus-rudiment.” A tooth is a paired structure in consequence of its composition of a double row of lamellag. A pair of lamellæ is its ultimate unit. A remarkable stage in the consolidation of these lamellæ is the cone-in-cone arrangement. The carina is formed by the beaks of the serially fitting cones. The ossicles of the lantern are compared with those of the mouth-frame of star-fish.—A. Lipschütz, C. Wagner, R. Tamm, and F. Bormann: Further experimental investigations on the hypertrophy of the sexual glands.
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Societies and Academies. Nature 110, 26–28 (1922). https://doi.org/10.1038/110026a0
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DOI: https://doi.org/10.1038/110026a0