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branched Alga, is indicative of the period of reproduction, 

 and terminates in the rupture of the individual cells, the 

 zoospores escaping through the apertures thus provided. 

 That this is the usual and true method of reproduction it is 

 easy to satisfy oneself in the following method. If a specimen 

 of Draparnaldia glomerata be kept in water, which ought not 

 to be renewed for a day or two, the cells will be observed to 

 separate from each other, and, floating on the surface of the 

 fluid, will be noticed a greenish pellicle : if a portion of this 

 be placed beneath the microscope, it will be found to consist 

 of a slimy material, in which are contained numerous green 

 globules of very minute size ; these, if watched for a day or 

 two, will be seen to take on the characters peculiar to the 

 species. 



The following observations in M. Decaisne's Memoir on 

 the Classification of the Alga in the Annales des Sciences 

 Naturelles occur, which correspond closely with the views 

 already expressed in reference to the reproduction of the 

 genus Draparnaldia, and which I have long entertained. 



" The Draparnaldia glomerata is composed, as it is known, 

 of a principal trunk formed by a series of large cells placed 

 upon each other, transparent, each occupied with a ring of 

 green matter, rather pale, mucous, and mixed up with amy- 

 laceous globules. The branches, which arise from the points 

 of junction of these cells, are themselves composed of articu- 

 lated ramuli, and terminated by a confervoid ciliform thread, 

 which, all united, produce the mucilage with which the plant 

 is found enveloped. 



" At the period when it has attained its complete develope- 

 ment, the hairs are seen to detach themselves successively 

 from the last joint : afterwards the green substance enclosed 

 in each of the ramuli unites into little globules, which escape 

 one after the other by a rounded aperture ( pratiquees ' upon 

 each of the cellules. These themselves become absorbed (se 

 resorbent) as soon as they are empty, so that at a period 

 more advanced, one finds of all the plant but a single filament 

 enveloped with mucus and filled with green globules. 



" I believe that I am able to conclude from these observ- 



i 3 



