Direction of the Inflected Tentacles.—When a particle of any kind is placed on the gland of one of the outer tentacles, this invariably moves towards the centre of the leaf; and so it is with all the tentacles of a leaf immersed in any exciting fluid. The glands of the exterior tentacles then form a ring round the middle part of the disc, as shown in a previous figure (fig. 4, [page 244] p. 10). The short tentacles within this ring still retain their vertical position, as they likewise do when a large object is placed on their glands, or when an insect is caught by them. In this latter case we can see that the inflection of the short central tentacles would be useless, as their glands are already in contact with their prey. FIG. 10. (Drosera rotundifolia.) Leaf (enlarged) with the tentacles inflected over a bit of meat placed on one side of the disc. The result is very different when a single gland on one side of the disc is excited, or a few in a group. These send an impulse to the surrounding tentacles, which do not now bend towards the centre of the leaf, but to the point of excitement. We owe this capital observation to Nitschke,* and since reading his paper a few years ago, I have repeatedly verified it. If a minute bit of meat be placed by the aid of a needle on a single gland, or on three or four together, halfway between the centre and the circumference of the disc, the directed movement of the surrounding tentacles is well exhibited. An accurate drawing of a leaf with meat in this position is here reproduced (fig. 10), and we see the tentacles, including some of the exterior ones, accurately directed to the point where the meat lay. But a much better * ‘Bot. Zeitung,’ 1860, p. 240. [page 245] plan is to place a particle of the phosphate of lime moistened with saliva on a single gland on one side of the disc of a large leaf, and another particle on a single gland on the opposite side. In four such trials the excitement was not sufficient to affect the outer tentacles, but all those near the two points were directed to them, so that two wheels were formed on the disc of the same leaf; the pedicels of the tentacles forming the spokes, and the glands united in a mass over the phosphate representing the axles. The precision with which each tentacle pointed to the particle was wonderful; so that in some cases I could detect no deviation from perfect accuracy. Thus, although the short tentacles in the middle of the disc do not bend when their glands are excited in a direct manner, yet if they receive a motor impulse from a point on one side, they direct themselves to the point equally well with the tentacles on the borders of the disc.