pure vegetative division, without any swarming move- 

 ment. It depends upon external conditions whether 

 the resting cells at once give rise to new active 

 generations, or to a series of quietly vegetating genera- 

 tions of cells. The formation and multiplication of 

 these vegetative generations takes place by the 

 division of the cell contents, either by simple divi- 

 sion, the first generation being transitory, or by 

 double halving. But the newly formed cells do not 

 slip out, as do the swarmers, from the mother-enve- 

 lope, they remain in the same place and position. 

 The membrane of the mother-cell seems to become 

 softened, expands, and becomes gradually drawn out 

 to nothing, and at length vanishes, the daughter-cells 

 in the mean time acquiring a tolerably thick, closely 

 applied, cell membrane of their own. The division 

 is repeated many times in this way, and as the cells 

 all remain in intimate contact, small families, and at 

 length large conglomerations of cells, are produced. 

 Ordinarily the colour is light brown. The above, 

 therefore, briefly represents the main features of the 

 life-history of this small organism, which has often 

 presented itself as a puzzle for the curious, but 

 presents many features of peculiar interest.''; 



Gory Dew. 



Another of the minute fresh-water algae, which is 

 known to botanists by the name of Porphyridiiim 

 cruentidii, has in times past caused considerable 



• For further details, consult " British Fresh Water Algse," by M. C. 

 Cooke, p. 51 (1882); Braun's " Rejuvenescence," p. 206; Cohn "On 

 Protococcus Pluvialis" (Ray Society, 1853). 



