Mr. HassalFs Notices of British Freshwater Alga. 181 



this Conjugata elsewhere in a manner very different from all the 

 others : the matter does not pass from one tube to another neigh- 

 bomnng tube, but each cell itself furnishes a single young plant, 

 the interior tube which it was found to enclose becoming a young 

 Conjugata which was entirely contained in the old tube, as it itself 

 contains the plants which are afterwards to become developed ; it 

 issues by the extremity when it occupies the last cell, and by the 

 sides when it is found in one of the central cells/' 



With respect to the observations of Vaucher in reference to 

 the germination of the young Conferva while still within the pa- 

 rent cell, I would observe that I have never witnessed this sin- 

 gular development, and can confidently assert that this is not the 

 legitimate or normal mode of development of the species of the 

 genus Mougeotia, which is by zoospores, developed external to the 

 cells, as in other Confervse. 



The above-detailed facts connected with the genus Mougeotia, 

 when viewed in connexion with other singular circumstances ex- 

 hibited by other abnormal forms of Confervse, are in the highest 

 degree important, from the light which they throw upon the 

 hitherto obscure physiology of this wide-spread class of Nature's 

 productions — proving as they clearly do the interesting fact, that 

 each cell 0/ every Conferva contains all the requisites for the per- 

 petuation of the species. Thus the occurrence of certain non- 

 conjugating species in the genus Zijgnema proves that union of 

 the filaments is not essentially concerned in the continuation of 

 the species of that genus ; while the single example met with in 

 the same genus of a species in which sporangia are formed without 

 either union of the filaments or commingling of the contents of 

 two cells — that is, are formed separately in each cell — clearly 

 testifies that this concentration of the endochrome of two cells is 

 likewise unessential to the continuance of the species of the ge- 

 nus Zygnema. Still further light is shed upon the reproduction 

 of the Confervse by Mougeotia ericetorum, the filaments of which 

 do not generally conjoin, but in which sometimes a union of the 

 matter of two cells in the same filament does take place, without 

 however any subsequent formation of sporangia ; the absence of 

 sporangia in this, as well as in the other species of the genus 

 Mougeotia, which differ however from M. ericetorum in that union 

 of the filaments does invariably occur, but unaccompanied by 

 transference of the endochrome, affording a proof conclusive of 

 the fact that the formation of sporangia is not indispensable to 

 the reproduction of the conjugating tribe of Confervse any more 

 than such sporangia are to that of the branched kinds, in which 

 there is no union of filaments, no transference of endochrome, 

 and no formation of sporangia. In the branched species, there- 



