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?

As the walls of the cells are necessarily permeable to fluids, in order to allow the glands to secrete, it is not surprising that they should readily allow fluids to pass inwards; and this inward passage would deserve to be called an act of absorption, if the fluids combined with the contents of the glands.  Judging from the evidence above given, the secreting glands of many other plants can absorb salts of ammonia, of which they must receive small quantities from the rain.  This is the case with two species of Saxifraga, and the glands of one of them apparently absorb matter from captured insects, and certainly from an infusion of raw meat.  There is, therefore, nothing anomalous in the Droseraceae having acquired the power of absorption in a much more highly developed degree.

It is a far more remarkable problem how the members of this family, and Pinguicula, and, as Dr. Hooker has recently shown, Nepenthes, could all have acquired the power of secreting a fluid which dissolves or digests animal matter.  The six genera of the Droseraceae very probably inherited this power from a common progenitor, but this cannot apply to [page 362] Pinguicula or Nepenthes, for these plants are not at all closely related to the Droceraceae.  But the difficulty is not nearly so great as it at first appears.  Firstly, the juices of many plants contain an acid, and, apparently, any acid serves for digestion.  Secondly, as Dr. Hooker has remarked in relation to the present subject in his address at Belfast (1874), and as Sachs repeatedly insists,* the embryos of some plants secrete a fluid which dissolves albuminous substances out of the endosperm; although the endosperm is not actually united with, only in contact with, the embryo.  All plants, moreover, have the power of dissolving albuminous or proteid substances, such