Mr. Hassall's Notices of British Freshwater Conferva. 387 



vesicules extrement petites, ordinairement munies, au centre, 

 d'un globule plus transparent, qui se colore soit en lilac, soit 

 en brun, par Paction de Piode." 



From what has been said of the true Confervae, it is evident 

 that both of the above definitions are full of error, in so far as 

 they have reference to the Confervae proper. Thus 1 have 

 shown that more than one spore is never contained in the 

 same cell ; that this spore is not formed, as described in the 

 first definition, at the expense of the green matter, " qui s'or- 

 ganise a, Finterieur de chacun des articles ou utricles qui 

 composent toute la plante," but from the concentration of 

 the matter in two contiguous cells of the same filament : nor, 

 as stated in the second, are they " extrement petites vesi- 

 cules," but large elliptical spheroidal or ovate bodies of the 

 same dimensions and structure as the similar bodies of the 

 Conjugates. 



I have shown, too, that the majority of the Confervae with 

 simple unbranched filaments are perpetuated by means of true 

 spores and not zoospores, and that these spores are in all these 

 cases formed in the same manner by the union and concentra- 

 tion of the contents of two cells, placed either, as in some but 

 not all Conjugate, in two distinct filaments, or in the same fila- 

 ment, as in the Vesiculaspermce and Sphmroplece, a statement 

 now for the first time promulgated, and upon the important 

 conclusion from which, with reference to the animality of the 

 Confervae and Spirogyrce in particular, I have already dwelt. 



The passage of the contents of one cell into the interior of 

 a contiguous one has not hitherto, I believe, been witnessed 

 by any observer. I was lately so fortunate as to notice the 

 manner of this transference in one of the species of the genus 

 Vesiculifera. It would appear not to be a momentary opera- 

 tion, but a continued action, being the result of a sustained 

 attraction existing between the contents of the two cells, but 

 most powerfully in that in which the seed is to be formed. 

 This attraction occasions the separation, at intervals of some 

 minutes, of three or four of the bright spherules, which, with a 

 thick colourless fluid, compose the contents of the cells, which, 

 when separated, immediately start into the seed-bearing cell, 

 and unite with the material already there. 



The tapering of the filaments alluded to in the definition of 

 the genus requires a careful examination for its detection, and 

 accounts satisfactorily for the variable size of the filaments in 

 the same species ; indeed, the more closely we study these 

 productions the more satisfactory will be the investigation of 

 them, and the fewer the number of the supposed anomalies. 



2 C2 



