250 THE PHENOMENON OF 



analogous to this zone of granules in the description of 

 the formation of the gonidia of Hydrodidyon. 



2. Reconstruction, with division into two daugliter- 

 cells, in the domain of fructification. 



a. The newly-formed cells are neither connected 

 together, nor with the membrane of the mother-cell. 

 The cells produced by division either divide anew (as 

 a transitory generation), without having acquired a 

 cell-membrane, or, if no fresh division occurs, they 

 are set free, naked and furnished with cilia, by tear- 

 ing of the mother-cell. Here belong the gonidia of 

 many Algae, of which mention has been already fre- 

 quently made. Either two gonidia are formed in one 

 mother-cell (by simple division of the contents), as in 

 Ulothrix Braunii (see pp. 177, 183), Aphanochate 

 repens (p. 1 84) ; or four, eight, sixteen, or thirty-two 

 gonidia, according as the division is repeated once or 

 more times, as in Ulva, Enteromorpha, Ulothrioc zonata 

 (p. 184), Characium (p. 185), Chlamidococcus (pp. 184, 

 206, &c.), &c. 



b. The newly-formed cells, free (active) at their birth, 

 become united into a regularly arranged colony after 

 birth. This occurs in Pediastrum (p. 184). 



c. The newly-formed cells become combined into 

 families before birth, either united by formation of firm 

 membranes, as in Scenedesmus (Niigeli, 'Einz. Algen/ 

 t. v. A), or held together by a development of gelatinous 

 matter, as is the case in the Volvocineae. 



B*. RECONSTRUCTION, WITH DIVISION, INTO TWO CELLS, 

 ONE OF WHICH REMAINS AS THE MOTHER-CELL, THE OTHER 



BEING SHUT OFF (ABGEGLIEDERT) AS A DAUGHTER-CELL. 



In the cases comprehended under B, the two cells formed 

 by the division of the mother-cell are either alike in every 

 particular, or, if they differ, take an equal share in 

 the process of Rejuvenescence through which they are 

 formed, appear both equally active agents in the re- 

 construction, and therefore are regarded as equal 

 daughter-cells of one mother-cell (destroyed by the 



