Sept. 1919,] THE GERMINATION AND DEVELOPMENT. 177 



The resulted two cells grow longer but a little thicker 

 than before, leaving the septal part of the tube in its former 

 diameter as a shallow constriction may be seen there. The 

 initial cell, /. e., the cell containing the sporangial part, ceases 

 to add to its length when it has attained about twice the 

 length of the diameter of the sporangial part. The other 

 tubular cell centinues its growth in length. At the end of the 

 second week after the resting of the spore, the tubular cell 

 is divided into two or three, more or less undulating, cjdindrical 

 cells, frecjuentlj' with evident decrease in the breadth they had 

 at first. Thus, the sporeling is now a protonema-like filament 

 in general appearance, with the initial cell at one end 

 (Fig. 6-7). 



Up to the above described stage, the germination of 

 Phyllitis-spores resembles the corresponding stage of develop- 

 ment of other Phaeophyceous members hitherto observed by 

 Thuret, Sauyageau, Reinke, and many others. Compared 

 also with Porphyra, a Florideae, we do not find any marked 

 difference in the essential mode of development. 



At the end of the second week and in the early part of the 

 third, the tubular cells grow in length and increase in number. 

 They var\' in diameter from 4// to 8^«, and in length from 30/^ 

 to 60//-. The chroraoplasts are single in each cell, except on the 

 way of cell-division, and are short C3dindrical with irregular 

 margins. They are usually at the middle of the cells and each 

 holds the nucleus inside. When compared with the initial cell, 

 the tubular cells have the chromoplasts thinner, hence paler in 

 colour, and smaller. 



The dispersed spores on the bottom of the beaker can 

 of course germinate freely. The tubular cells creep on the 

 substratum growing in length and increasing in number. 

 The aggregated spores appear to find great trouble in their 

 development. As the\' increase in size, they press against each 

 other and the middle part of a heap of spores bulges out as its 

 under surface comes off the substratum. The spores in the 

 heaps germinate slowU^ and develop very poorlj'- in comparison 

 with the solitarv ones. 



