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Show 10 DROSERA ROTUNDIFOLIA. · CuAP. I. The tentacles in the act of inflection sweep through a wide space; thus a marginal tentacle, extended in the same plane with the blade, moves through an angle of 180°; and I have seen the much reflected tentacles of a leaf which stood upright move through an angle of not less than 270°. The bending part is almost confined to a short space near the base; but a rather larger portion of the elongated exterior tcntaclt:R FIG. 4, (Drose1·a rotundifolia.) Leaf (enlarged) with all the tentacles · closely inflected, from immersion in a solution of phosphate of ammonia (one part to 87,500 of water). Frc . ;;, (D1·osem ?'Otundif olia .) J~eaf (enlarged) with the tentacl ~on one side inft cte<l over a bit oi meat placed on the disc. becomes slightly incurved; the distal half in all cases remaining straight. The short tentacles in the centre of the disc when directly excited, do not become inflected; but they are capable of inflection if excited by a motor impulse received from other glands at a distance. Thus, if a leaf is immersed in an infusion of raw meat, or in a weak solution of ammonia (if the CHAP. I. ACTION OF THE PARTS. 11 solution is at all strong, the leaf is paralysed), all the exterior tentacles bend inwards (see fig. 4), excepting those near the centre, which remain upright ; but these bend towards any exciting object placed on one side of the disc, as shown in fig. 5. The glands in fig. 4 may be seen to form a dark ring round the centre; and this follows from the exterior tentacles increasing in length in due proportion, as they stand nearer to the circumference. The kind of inflection which the tentacles undergo is best shown when the gland of one of the long exterior Fro. 6. (Drosera rotundifolia.) c Diagram showing one of the exterior tentacles closely inflected ; the two adjoining ones in their ordinary position. tentacles is in any way excited; for the surrounding ones remain unaffected. In the accompanying outline (fig. 6) we see one tentacle, on which a particle .of meat had been placed, thus bent towards the centre of the leaf, with two others retaining their original position. A gland may be excited by being simply touched three or four times, or by prolonged contact with organic or inorganic objects, and various fluids. I have distinctly seen, through a lens, a tentacle beginning to bend in ten seconds, after an object had been |