THE HIGHER CRYPTOGAM EA. 177 



is accompanied by continual revolution of the body round 

 its own axis : that is, round the axis of the spiral. Be- 

 fore maturity the spermatozoa are enclosed in quadran- 

 gular cells. Later observations have only added one fact 

 to those of Unger, viz., that the thin fore- end of the 

 spermatozoon bears two long oscillating cilia (Thuret, 

 ' Ann. Sc. Nat./ ii Ser., vol. xiv, p. GS, and iii Ser., vol. 

 xvi, p. 73; Schimper, 'Rech. sur les Mousses/ pi. xv, 

 tigs. .25 29 ; ' Mem. sur les Sphaignes/ pi. viii, figs. 23 

 25). Unger noticed the cuticle of the antheridia of 

 Sphagnum, but could not decide whether the structureless 

 membrane, which is capable of being detached from the 

 chlorophyll-bearing cells of the covering layer, was on 

 the outside, or on the inside of those cells. He was in- 

 clined to assume the latter. Schleiden seems to have 

 fallen altogether into the mistake of supposing the cuticle 

 to be the membrane of a large central cell of the anthe- 

 ridium surrounded by the covering layer, for he alleges 

 (' Grundzuge/ ed. iii, p. 577), that this organ in Sphag- 

 num is a stalked oval sac, formed of a large central cell, 

 and a surrounding cellular layer. This erroneous state- 

 ment has been entirely refuted by P. W. Schimper (' Rech. 

 sur les Mousses,' p. 52), by means of the history which 

 he gives of the development of the antheridia, and also 

 by his accurate description of the anatomical structure 

 of these organs when they are mature and ruptured. 



In the same manner as he has done in the case of the 

 antheridia, P. W. Schimper has recognised the rudi- 

 mentary formation of the archegonia, by means of the di- 

 vision, by septa inclined in different directions, of an out- 

 wardly-protruding papillary cell of the external surface 

 of the apex of the stem. This division is continually re- 

 peated in the apical cell of the cellular body, as it gra- 

 dually becomes cylindrical. 



Until the publication of my observations, however, the 

 continental botanists attained no greater knowledge of the 

 structure of the archegonium when ready for impregnation, 

 than was possessed by Hedwig. 



In the mean time, in the year 1833, Valentine had dis- 

 covered the simple rudimentary cell of the moss-fruit, in 



12 



