THE HIGHER CRYPTOGAMIA. 327 



that it is more massive, and differs from Pilularia in the 

 subordinate point that the cells which form the mouth of 

 the passage leading to the central cell do not become papil- 

 late. Here, as there, the entire prothallium is devoted to 

 the formation of one archegonium. 



The spores of Marsilea which came under my observation 

 did not become further developed. „ The small spores pro- 

 cured contemporaneously from the same fruit,* which was 

 8 J years old, exhibited no change : it would seem that these 

 latter lose their power of germination sooner than the large 

 spores. The prothallia died when they had attained the 

 stage of development necessary for impregnation, inasmuch 

 as the small spores mingled in the surrounding fluid de- 

 veloped no spermatozoa. I observed the same phenomenon 

 in Pilularia minuta. 



* For which I was indebted to the kindness of Alexander Braun. They 

 were part of the same gathering which yielded the materials for his and Mette- 

 nius's observations, and were found at Montpelier in 1842. 



