274 M. W. Hofmeister on the Fertilisation of Ferns. 



the entrance of this appeared almost closed by the expansion of 

 the neighbouring cells. This growing up of the internal mouth 

 of the canal evidently followed immediately the entrance of the 

 spermatozoid into the central cell. This is the first phenomenon 

 which gives evidence of the completion of the fertilization, 

 and not, as I formerly assumed (Vergleich. Unters. p. 82), 

 the division of some of the cells immediately surrounding the 

 central cell. The number of these is very variable in unfertilized 

 archegonia of the above-mentioned species. The impregnated 

 germinal vesicle enlarges until it fills the central cell, and then 

 commences its series of divisions (segmentation) which lay the 

 foundation of the various organs of the embryo. 



In the Mosses also, the central cell of the archegonium be- 

 haves as an embryo-sac. There again the germinal vesicle is 

 found around a nucleus appearing free near (under) the primary 

 nucleus ; shortly before the formation of the canal leading- 

 through the neck of the archegonium, formed by the dissolution 

 of the axile row of cells of the latter. The new canal lies in the 

 lower convexity of the central cell, — its position, and that of the 

 young germinal vesicle, are therefore opposite to those of the 

 same organs in the vascular Cryptogamia. The primary nucleus 

 soon disappears, the germinal vesicle grows considerably, and in 

 the mature archegonium more than half fills the central cell. 

 In the Mosses it mostly floats free in the centre ; more rarely it 

 adheres to the side or the upper part of the wall, which, in the 

 archegonium ready for impregnation, softens into a jelly, but 

 does not completely dissolve. In Hepaticse with very large 

 cavity of the archegonium, such as Riccia, Riella and Fossom- 

 bronia, the germinal vesicle often rests against some point of the 

 upper convexity, projecting freely into the cavity. I have no 

 doubt that spermatozoids of the Mosses pass the cord of mucus 

 (strongly refracting light) which occupies the axis of the canal 

 of the archegonium and projects a short distance into its ex- 

 panded portion, that they enter into the latter and come in con- 

 tact with the outer surface of the germinal vesicle. I am the 

 more confident from having found moving spermatozoids, in 

 Funaria hyyrometrica, which had penetrated down one-third of 

 the length of the neck of the archegonium. The tenuity of the 

 spermatozoids and the want of transparency in the walls of the 

 archegonium, will be a sufficient apology for the further fate of 

 the spermatozoids not having yet been observed here. 



