other writer, and, from having discovered or described a numberof new species, lie had more materials to assist him in gene-ralizing his observations. Chcetophora, however, as establishedeven by him. will, I am persuaded, not long be retained ; andMr Gray has already divided it, though not judiciously.Until more is known respecting these plants, I prefer followingLyngbye, whose definition of the genus is at least simple andeasily understood.

According to him, we have in this country the followingChcetophorce:

Ch. endivifolia, Ulva incrassata, Eng. Bot. t. 967-

Ch. elegans, Ag. Found by me near Edinburgh .

Ch. marinay Iiivularia tuberiformis, Eng. Bot. but not quoted byLyngbye.

Mr Gray has added to our flora Ch. plana, Ag. which isnot described by Lyngbye ; and as I have not seen it, I can-not determine whether it really belongs to the genus. MrGray, as usual, has given us no authority for this new Britishplant, nor even mentioned where it was found.

Chsetophora marina , in old age, seems, from the figure iflEnglish Botany, to burst and become lacerated,—a state inwhich I never found it. When floating in the sea, we are toldin the same work, that it looks “ extremely like an assemblageof young potatoes.” I have not hesitated to re-figure it, as thehabit is not correctly represented by Sowerby, and the dis-section imperfect: besides which, it is described in that excel-lent work as a new plant, an error it is desirable to correct.

In regard to the fructification, Lyngbye is silent, exceptin calling the summits of the filaments granuliferous. Thesesummits I certainly consider reproductive. The 3 or 4 seeds,disposed the one over the other, mentioned by Sir J. E. Smith ,I never could detect, nor has Lyngbye noticed them. MrGray’s “ spores” in the swollen joints are surely imaginary.

Fig. 1. Plants, not. size, on rock, and on Corallina officinalis. Fig. 2. H sec 'lion of a full-sized plant, and of a small one at its full grorvth. Fig-Masses off laments, with their terminating granules.