80 On the development of the Spores of Anthoceros lasvis. 



As to the analogy which I have indicated exists between the 

 formation of the Sporae and that of the pollenic grains, M. 

 de Mirbel announces that there exists a constant difference 

 in the manner by which these two organisms become deve- 

 loped, so that in the Sporae the mother-cellule, after that 

 the four Sporae are formed, becomes divided into four 

 cellules, which in consequence of the increasing volume of 

 the Sporae, become shrivelled and lacerate, whilst the four 

 compartments into which the mother-cellules of the pollenic 

 grains are divided by septa, do not become separated from 

 each other. 



The inquiries which I have published on the development 

 of Sporae (Flora, 1833; Archives de Bot. ii. 341) agree with 

 the results obtained by M. de Mirbel in this, that in descend- 

 ing to the Lichens (with the exception of the Equisetaceae) 

 there was developed four Sporae in one mother-cellule ; that 

 in these latter, and before the development of the Sporae, 

 we found a liquid granular substance ; and this became di- 

 vided afterwards into four parts, which then became covered 

 with a peculiar membrane. But as to the manner by which 

 the membrane of the Sporae became formed, my results 

 differ from those obtained by the French physiologist. 

 Thus, I think in consequence, particularly of the examina- 

 tion of Riccia glauca and of the Anthoceros lavis, I have a 

 right to admit that the granular mass which fills the mother- 

 cellule becomes divided of itself into four parts, and is not 

 as it were divided by the partitions which direct themselves 

 from the circumference of the cellules to the centre ; that 

 each of these parts become covered first by a thin and 

 homogenous membrane, around which after a time a second 

 external membrane is formed, which very often becomes 

 cellular ; that those four Sporae become surrounded again on 

 every part by the close mother-cellule, and that this latter 

 becomes absorbed without previously being divided. The 

 points on which I differ in opinion from M. de Mirbel, re- 



