Abstract
THE November number of the Monthly Microscopical Journal commences with a paper by Dr. R. L. Maddox on an organism found in Fresh-pond Water, which he thinks to be new. The accompanying illustration, as well as the description, shows that the monads under consideration are of the simplest structure, and amæboid in character, of a violettint, and highly refracting. They vary in size, and contain great numbers of little granular bodies embedded in the gelatinous matrix. The name Pseudoamæha violacea is proposed for the new form.—Mr. F. Kitton describes some new species of Diatomacea;, including Aulaco-discus superbus from Barbadoes, and others of the genera Sticto-discus, Isthmia, Nitzschia, and Tryblionella.—Mr. Carruthers answers Dr. Dawson's comments on his interpretation of the microscopic appearances of Nematophycus (Carruthers) or Protolaxites (Dawson). As he remarks, the question whether the plant under consideration is a sea-weed or a conifer, is entirely an histological one. Dr. Dawson, in his sections of the fossil found “wood cells, showing spiral fibres and obscure pores;” Mr. Carruthers finds “elongated cylindrical cells of two sizes, interwoven irregularly into a felted mass,” and the latter observer substantiates the correctness of his observations and his drawings, which prove the accuracy of his views as to the affinities of the plant.—Mr. J. J. Woodward explains the optical principles involved in the construction of Mr. Tolles' new immersion objective that has caused the contest between him and Mr. Wenham.—Dr. Braithwaite continues his description of bog mosses, treating of figuring Sphagnum rigidum and S. molle.— This paper is followed by one on the investigation of Microscopic Forms by means of the images which they furnish of external objects, by Prof. O. N. Rood, of Troy, N.Y., which gives an extremely ingenious and simple method of testing with certainty, when the refractive indices of the body examined and the fluid in which it is immersed, are known, of determining whether markings, as of Coscinodiscus triceratium, are depressions or elevations; by regarding the object as part of the optical system, and thence finding whether its influence is that of a convex or concave lense.
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Scientific Serials . Nature 9, 55 (1873). https://doi.org/10.1038/009055a0
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DOI: https://doi.org/10.1038/009055a0