32 



Veit Brechek Wittrock. 



and rounded surface of the protoplasm a protecting cell-wall. In this 

 manner two new and complete cells have been formed by the remains 

 of the damaged protoplasmatic body. The same proceeding has taken 

 place in the greater of the two branch cells; with this difference only, 

 that the parasites have here le£t protoplasm only in one of the ends of 

 the cell, and that the remaining quantity of protoplasm has been smaller 

 still than in any of the tw T o cases mentioned above. The facts related 

 here may serve as a proof of the great power which the protoplasm 

 has (at least in elongated cells belonging to the lower algae) *) of hea- 

 ling wounds whieh have been inflicted upon it. 



IV. BRIEF RECAPITULATION OF THE WHOLE DEVELOPMENT- 

 PROCESS. 



When the spore germinates (the germination takes place in water), 

 it is elongated in two opposite directions. A transversal parting-wall is 

 formed in that part of the germ-cell, which has belonged to the germi- 

 nated spore. By this the germ-cell is divided into two daughter cells, of 

 which the one gives rise, by continued bipartition, to the ramified part 

 of the thallus, which serves for propagation, the cauloid; whilst the 

 other, which generally has not the power of further development, forms 

 alone the antipode of the cauloid, the rhizoid. The development of 

 the caulo'id takes place in the following manner. The first cauloid cell, 

 formed immediately at the germination of the spore, is elongated, and 

 divides by common bipartition into two daughter cells. In the lower one 

 of these, no further formation of vegetative cells takes place. But the 

 upper acts in the same manner as the mother cell, is elongated and 

 divides. The two new daughter cells thus formed now proceed in the 

 same manner as the daughter cells formed by the division of the first 

 cauloid cell; and afterwards the same proceeding is continued as long 

 as the development in length continues. Thus, the increase is, in short, 

 terminal. The series of cells formed in this manner, the principal 

 filament, now ramifies in the following manner. Every cell that is to 

 form a branch sends forth, a small space below its top, a process 



l ) In the elongated and ramified vegetative cell of the Vaucheria I have 

 more than once observed the same occurrence. Compare besides Hanstein, Leb. d. 

 Yauch., Bot. Zeit. 1873, pag. 097. 



