Dr. G. Dickie on the Physiology of Fecundation in Plants. 5 cludenti. Tentacula nulla. Branchiae styliformes dorsi late-ribus utrinque affixae. Anus subposticus in medio dorso. Aper-tura sexualis pone caput in latere dextro. Species unica A. modesta^, Loven. Hab. in limo, locis maritimis parum profundis. II. — Contributions to the Physiology of Fecundation in Plants. By G. Dickie, M.D., Lecturer on Botany in the University and King's College of Aberdeen f. [With a Plate.] Although many interesting observations respecting fecundation in plants were contributed by the older botanists, it is chiefly to observers of the present century that we owe the facts now known respecting the structure of the ovule, its development previous to, and further progress after impregnation. The contributions of Brown, Amici, Brongniart, Mirbel and others to this depart-ment are invaluable, and when Schleiden in 1837 announced the ''grand doctrine^' as it has been called, that the extremity of the pollen-tube reaches the embryo-sac, indents it, carries it before it, and is itself then actually converted into the embryo, physio-logists who formerly had written on this subject were stimulated to repeat their inquiries, new observers also entered the field, and the rash generalization of the observer alluded to has actually been the means of furnishing important additions to our know-ledge of this most interesting branch of vegetable physiology. It can scarcely be doubted that much still remains to be known re-specting this subject, and judging from the history of its progress, an accurate and complete acquaintance with it can only be arrived at by degrees and by the efforts of different observers. The quaint remarks of Nehemiah Grew, in his ' Anatomy of Plants,^ appear to be so applicable to this matter, that no apology need be made for quoting them ; he says, " That nothing hereof re-maineth further to be known is a thought not well calculated. For if we consider how long and gradual a journey the know-ledge of nature is, and how short a time we have to proceed therein j as on the one hand we shall conclude it our ease and profit to see how far others have gone before us, so shall we be-ware on the other, that we conceive not unduly of nature, whilst * Though Loven 's specific name, modestus, was evidently given to con-itrast with ornatus, the name of Ehrenberg's species, I have nevertheless ab-tained from changing it, though the congeneric relationship with Stiliger has been broken, and the name been consequently deprived of its original significance. t Read before the Botanical Society of Edinburgh, Nov. 13, 1845.