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 590 to Lepidostrobus, be really distinct from that genus; and although there are still several points of difference remaining, namely, the form of the strobilus in Triplosporite, confirmed by a second specimen presently to be noticed, and in Lepidostrobus the more limited insertion of sporangium, and the very remarkable difference in the form of the unripe spores, hardly reconcilable with a similar origin to that described in Triplosporite, I am upon the whole inclined to reduce my fossil to Lepidostrobus until we are, from still more complete specimens of that genus, better able to judge of the value of these differences. The name Triplosporites, however, is already adopted, and a correct generic character given, in the second edition of Professor Unger's 'Genera et Species Plantarum Fossilium,' p. 270, published in 1850, who at the date of his preface in 1849 was not aware of Dr. Hooker's essay on Lepidostrobus, the character of which he has adopted entirely from M. Brongniart's account.

In October 1849 M. Brongniart showed me a fossil so closely resembling the Lepidostrobus both in form and size, that at first sight I concluded it was the lower half of the same strobilus. On examination, however, it proved to be of somewhat greater diameter. It was nearly in the same mineral state, except that the crystallizations consequent on loss of substance were rather less numerous; it differed also in the central part of the axis being still more complete; in the bracteæ being more distant and of a slightly different 474] form: but the spores in composition, form, and apparently in size were identical. This specimen had then very recently been received from the Strasburg Museum, but nothing was known of its origin or history.

May 5, 1851.