. Synopsis of the naviculoid diatoms. Presented to the R. Swedish Academy of Sciences May 10, 1893. Diatoms. Tropidoneis concerta, 600 times magniiied. Tropidoneis Lepidoptera, 500 times . magnified. valves of Plagiotropis there is frequently a longitudinal band, the nature of which is not quite clear to me. It may be a wing, or a crest, as in many Nitzschiese, or perhaps a furrow. Tropidoneis' has evidently a close affinity with the Nitzschise of tbe Grunowian divisions Bilobatse and Pseudo-amphiprora. Among the Kaphidiese it may be akin to the carinated forms of Gryrosigma, or the so called
. Synopsis of the naviculoid diatoms. Presented to the R. Swedish Academy of Sciences May 10, 1893. Diatoms. Tropidoneis concerta, 600 times magniiied. Tropidoneis Lepidoptera, 500 times . magnified. valves of Plagiotropis there is frequently a longitudinal band, the nature of which is not quite clear to me. It may be a wing, or a crest, as in many Nitzschiese, or perhaps a furrow. Tropidoneis' has evidently a close affinity with the Nitzschise of tbe Grunowian divisions Bilobatse and Pseudo-amphiprora. Among the Kaphidiese it may be akin to the carinated forms of Gryrosigma, or the so called Donkinise. It is also closely related to the Naviculse of the section fusiformes which, although their valves are not keeled, agree with Tropidoneis in the nature of the sculpture of their values, in then non-complex zones, and in thei approximate central pores of their median lines., The species of Tropidoneis do not inhabit fresh water. Forms of the section Plagiotropis are very frequent in brackish water. The large, wingless forms of Orthotropis. are pelagic in their habits, and the winged, marine. They occur in all parts of the world from the arctic seas to the tropical, 'iifi â '.»>'â¢' -s"**/ *f. The forms of Tropidoneis are in many cases very imperfectly known, so that several species are to be regarded as doubtful. The study of them is difficult, especially as regards the nature of the wings, which require a favourable position of the valves for their examination. Artificial key. I. Orthotropis, median line central or nearly central. ^ j Valve without wings ;. t â witli â I Valve moderately high \ â very high . .;â ..â ':â . ⢠. .t Z lih ,â / â â¢'(.â â â na Jl «'> -il â¢liii.'S'llH .' . 2. . 5. t' T. adriatica 3. Cl.' >!â '.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectdiatoms, bookyear1894
