CHAP, i.] Sexuality in Cryptogams. 44 1

thrown a clear light on the character of the male and female organs, and on the way in which the embryo is formed by repeated division of the egg-cell present before fertilisation, we continued quite in the dark respecting the particular nature of the fertilisation. Observation and experiment had estab- lished the fact, that the influence of the spermatozoids on the archegonia was required to produce an embryo in the latter. Female moss-plants 1 separated from the male, macrospores in the Vascular Cryptogams separated from the microspores, had in all cases proved unproductive ; but it was not even certainly known to what point in the female organ the spermatozoids force their way. It is true that Lesczyc and after him Mercklin had seen the entry of moving spermatozoids into the mouth of archegonia in Ferns ; but Lesczyc's account of the part which he supposed them to play there afterwards, was proved to be an illusion. I had myself observed motionless spermatozoids halfway down the neck of archegonia of an Equisetum ; but nothing was to be learnt of the manner in which the spermatozoid affects the egg-cell. Then it happened that in the spring of 1851, being engaged in observing the development of the organs of vegetation of Ferns, I repeatedly saw spermatozoids moving about in the basilar cells which en- close the egg-cell in the archegonia of Ferns, and the majority of them even playing about the egg-cell. Their movements were put an end to during the observation by the commencement of changes, which the contents of young vegetable cells which have been cut open usually experience under the prolonged influence of water.' Later observations leave no doubt now that in the Muscineae and Ferns single spermatozoids force their way into the naked egg-cell of the archegonium.

' \V. P. Schimper, in his ' Rechcrches anatomiques et morphologiqucs sur Ics Mousses 'of 1850, had made some important statements respecting the sterility of female moss-plants growing at a distance from male speci- mens, and proved that the presence of male plants among females that arc-

otherwise barren renders them fruit fid.