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the contents has recently begun, we find that the single parts of 

 the contents are separated from each other by a rather large open 

 space, larger perhaps owing to the influence of the alcohol than 

 in the living plant. These parts are surrounded by a mem- 

 brane and then, as we see lower down, where the cell division 

 J s in a more advanced stage of development, they grow 

 quite near each other and are no longer separated. The apical 

 cell is also divided later on in this way. When these cell parts or 

 cells, as we may now call them, have reached a certain degree of 

 maturity they all with exception of the top cell begin to grow out 

 in their uppermost end into two opposite branches lying in the 

 same plane as the whole frond (see the lowermost branches in 

 fig. 14 c). These new branches again grow out to a certain length 

 and then they divide quite in the same way and so on. In fig. 14 a 

 we see the uppermost part of a young stalk in about the same 

 stage of development as the last-mentioned side branches in fig. 

 14c; and fig. 14 b shows a more advanced stage, where the side 

 branches have grown much longer but are yet undivided. In my 

 material I have not succeeded in finding the first beginning of the 

 cell division in the stalk, this at first being a long cylindrical cell 

 with no walls at all, but I have no doubt that this is performed 

 quite in the same way as mentioned above with regard to the 

 side-branches. 



This method of cell division reminds one very much of that 

 described above in Dictyosphceria and of that found in Siphono- 

 cladus tropicus as I have described it 1. c. and Dr. R o s e n v i n g e 

 has also directed my attention to that found in the formation of 

 the zoosporangium of Vaucheria (cfr. Götz in "Flora", vol. 83, 

 1897, p. 93 and the literature quoted here). 



The ramification of the branches can take place several times; 

 in an old frond I have found branches of the 4 th order. While 

 the branching is very regular in the young specimens, as the figure 

 shows, the ramification in the older, leaves is more anomalous, 

 branches of the highest order being not formed everywhere (fig. 14 d). 



At the same time as the side branches of first order have 

 begun to divide, the top cells of each branch develop at their 

 apices rhizoid-like organs of attachment which Murray and 

 Boodle have called "tenacula". These consist of a little cell 

 (fig. 14 e) ending in a broader, irregularly lobed disc, by means of 

 which the top cell of each of the inward bent branches fastens itself 



