A Synopsis of the British Diatomaceæ: With Remarks on Their Structure, Functions and Distribution; and Instructions for Collecting and Preserving Specimens, Band 1

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Smith and Beck, Pub., 1853 - 89 Seiten
 

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Seite xxii - is not avoided, but pushed aside ; or, if it be sufficient to avert the onward course of the frustule, the latter is detained for a time equal to that which it would have occupied in its forward progression, and then retires from the impediment, as if it had accomplished its full course.
Seite xxx - in a tolerably clean state ; all that is necessary being, to place the gathering which contains them in a shallow vessel, and leave them undisturbed for a 'sufficient length of time in the sunlight, and then carefully to remove them from the surface of the mud or water.
Seite xiii - intermixed with the scum of living or decayed vegetation floating on the surface of the water. Their colour is usually a yellowish brown of a greater or less intensity, varying from a light chestnut in individual specimens, to a shade almost approaching black in the aggregated masses.
Seite xxx - Let him provide himself in the first place with the necessary apparatus. For the field, this includes a good stock of small wide-mouthed bottles, that each gathering may be kept perfectly distinct ; a long rod or stick, to which can be attached a small muslin net ; a
Seite xxiv - in others of an elliptical or orbicular outline, in which foramina exist along the entire line of suture, the movements, if any, must be irregular, or slowly lateral. Such is precisely the case. The backward and forward movements of the
Seite xxiii - Among the hundreds of species which I have examined in every stage of growth and phase of movement, aided by glasses which have never been surpassed for clearness and definition, I have never been able to detect any semblance of a motile organ ; nor have I, by
Seite xi - are stones of mountain streams or waterfalls, and the shallow pools left by the retiring tide at the mouths of our larger rivers. They are not however confined to the localities I have mentioned,—they are in fact
Seite xxiv - the motion be produced by the exosmose taking place alternately at one and the other extremity, while endosmose is proceeding at the other, an alternating movement would be the result in frustules of a linear form
Seite xxxi - that the specimens can be submitted without further preparation to a heat sufficient to remove all the cell-contents and softer parts, leaving the siliceous epiderm in a transparent state.
Seite xviii - the extremities, where the Foramina, already described, exist. Nor does the valve, when fractured, show any disposition to break at the expansions of the central line, as would necessarily be the case were such points perforations, and not nodules.

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