examined, a succession of hermaphrodite flowers may be observed at intervals throughout the whole summer, from the beginning of May to the end of August; and that, in fact, about every fifth flower is hermaphrodite.
With, these observations of Karsten the present report comes to a close; and the readers of it, being now in possession of the evidence on both sides, may form their own opinion whether or not parthenogenesis exists in the vegetable world. It is no part of the duty of the writer of a report to give his own views upon the subject to which it relates, although we ventured a statement at the outset that the point in dispute was far from decided. Setting aside the case of Cœlebogyne, it appears to the writer that, although some of the facts might lead to a suspicion on the subject, there is really no proof whatever of the existence of parthenogenesis, at least, in phamogamic plants; and with regard to the Cryptogamia, the discovery of their sexual organs is of such comparatively recent date, and the examination of them is surrounded by so many difficulties, and is in the hands of so few observers, that it would be rash in the extreme to found any theory upon the results hitherto obtained. Cœlebogyne, however, still remains a striking instance of the apparent possibility of reproduction without impregnation; for, although the value of the evidence afforded by this latter plant is doubtless shaken by Karsten's observations, it is quite impossible to assume, with him, that parthenogenesis is yet disproved. It cannot be supposed that the observations of Smith, Radlkofer, Deecke, and Braun have been so imperfectly and carelessly conducted as must be the case if, as Karsten would lead us to suppose, every fifth flower in every plant of Coœlebogyne is hermaphrodite. We do not at all intend to deny the correctness of his observations, but we think it highly improbable that, if the stamens of Cœlebogyne were of such frequent occurrence, they would have escaped the notice of so many other equally able observers.
In conclusion, it is hardly necessary to remark, that further observations by competent botanists, as to the anatomy of the inflorescence of Cœlebogyne, are much to be desired; and that further inquiries into the reproductive process in cryptogamic plants may hereafter throw additional fight upon the subject. For the present, all that can be said is that vegetable parthenogenesis is not proven.
XLVII.—On the Systematic Arrangement of the Rhizopoda.
By William B. Carpenter, M.D. F.R.S., &c.
Notwithstanding that, by the general consent of zoologists, the group of Rhizopods is now admitted to take rank as a class in the sub-kingdom Protozoa, and although there is little or no difference of opinion as to the extent of range which it comprehends, scarcely anything has yet been done towards the determination of the prin-
