** Dr. Warming ‘Sur la Diffrence entres les Trichomes,’ Copenhague, 1873, p. 6. ‘Extrait des Videnskabelige Meddelelser de la Soc. d’Hist. nat. de Copenhague,’ Nos. 10-12, 1872. [page 360] power was transferred to the basal parts of the hairs, or that the surface of the leaf has been prolonged upwards at numerous points, so as to unite with the hairs, thus forming the bases of the inner tentacles. The above named three genera, namely Drosophyllum, Roridula, and Byblis, which appear to have retained a primordial condition, still bear glandular hairs on both surfaces of their leaves; but those on the lower surface have since disappeared in the more highly developed genera, with the partial exception of one species, Drosera binata. The small sessile glands have also disappeared in some of the genera, being replaced in Roridula by hairs, and in most species of Drosera by absorbent papillae. Drosera binata, with its linear and bifurcating leaves, is in an intermediate condition. It still bears some sessile glands on both surfaces of the leaves, and on the lower surface a few irregularly placed tentacles, which are incapable of movement. A further slight change would convert the linear leaves of this latter species into the oblong leaves of Drosera anglica, and these might easily pass into orbicular ones with footstalks, like those of Drosera rotundifolia. The footstalks of this latter species bear multicellular hairs, which we have good reason to believe represent aborted tentacles. The parent form of Dionaea and Aldrovanda seems to have been closely allied to Drosera, and to have had rounded leaves, supported on distinct footstalks, and furnished with tentacles all round the circumference, with other tentacles and sessile glands on the upper surface. I think so because the marginal spikes of Dionaea apparently represent the extreme marginal tentacles of Drosera, the six (sometimes eight) sensitive filaments on the upper surface, as well as the more numerous ones in Aldrovanda, representing the central [page 361] tentacles of Drosera, with their glands aborted, but their sensitiveness retained. Under this point of view we should bear in mind that the summits of the tentacles of Drosera, close beneath the glands, are sensitive. The three most remarkable characters possessed by the several members of the Droseraceae consist in the leaves of some having the power of movement when excited, in their glands secreting a fluid which digests animal matter, and in their absorption of the digested matter. Can any light be thrown on the steps by which these remarkable powers were gradually acquired?