3.
ON THE STRUCTURE OF THE UNIMPREGNATED OVULUM IN PHAENOGAMOUS PLANTS.
The description which I have given of the Ovulum of Kingia, though essentially different from the accounts hitherto published of that organ before fecundation, in reality agrees with its ordinary structure in Phaenogamous plants.
I shall endeavour to establish these two points; namely, the agreement of this description with the usual structure of the Ovulum, and its essential difference from the accounts of other observers, as briefly as possible at present; in tending hereafter to treat the subject at greater length, and also with other views.
I have formerly more than once* adverted to the structure of the Ovulum, chiefly as to the indications it affords, even before fecundation, of the place and direction of the future Embryo.

These remarks, however, which were certainly very brief, seem entirely to have escaped the notice of those authors who have since written on the same subject.
(*Footnote.

Flinders Voyage 2 page 601, and Linnean Society Transactions 12 page page 136.) In the Botanical Appendix to the account of Captain Flinders' Voyage, published in 1814, the following description of the Ovulum of Cephalotus follicularis is given: Ovulum erectum, intra testam membranaceam continens sacculum pendulum, magnitudine cavitatis testae, and in reference to this description, I have in the same place remarked that, "from the structure of the Ovulum, even in the unimpregnated state, I entertain no doubt that the radicle of the Embryo points to the umbilicus."* (*Footnote.

Flinders Voyage loc.

cit.) My attention had been first directed to this subject in 1809, in consequence of the opinion I had then formed of the function of the Chalaza in seeds;* and sometime before the publication of the observation now quoted, I had ascertained that in Phaenogamous plants the unimpregnated Ovulum very generally consisted of two concentric membranes, or coats, enclosing a Nucleus of a pulpy cellular texture.