74 NOTES AND MEMORANDA. 



municated to the Lyceum of Natural History (New York) , 

 some observations on this subject. 



The plant he examined belonged to the genus CEdogonmm 

 of Link, but the particular species Avas undetermined. The 

 perfect plant itself consists of an extremely fine, green-colored 

 filament, cylindrical in form, and having its frond divided at 

 regular intervals by partition walls, so that the individual 

 plant may be represented by a series of tubular cells or boxes, 

 like tall pill-boxes, united end to end. 



" The mode of reproduction known to exist is (says Pro- 

 fessor Edwards) by the shrinking inwards of the inner cell- 

 membrane, commonly known as the ' Primordial Utricle' of 

 Mohl, and enclosing the cell-contents, away from the tough 

 cellulose coat, while at the same time the cell-contents 

 themselves assume a more or less coarsely-granular condition, 

 apparently from the enlargement of the individual particles 

 of which it is made up. It is recorded that thereafter, at a 

 certain period in this change, the outer cell-wall splits across 

 at a point near to one end of the cell, and, wliile the lid so 

 formed remains attached to one side the other and largest 

 portion, the cell contents escape from the cavity into the 

 surrounding water, and gradually assume the spherical form. 

 Thereafter there is developed upon one side of the sphere a 

 ring of cilia which become more and more active until, at 

 last, they move about Avith such energy that the little green 

 globe assumes an extremely active motile condition. In this 

 state it has been called a ' motile spore.' 



" Up to this period our record, as hitherto published, is 

 complete, but just here is a gap and it has been my good 

 fortune to make such observations as fill it and complete 

 our knowledge of the life history of this plant. Tlie changes 

 and transformations which I now record, I have seen not 

 merely a few times, but perhaps, thirty or forty, so that I am 

 enabled to speak confidently as to the accuracy of my notes, 

 as I have Avatched the Avhole process. It is as folloAvs. At 

 first the bright green-coloured cell-contents, around and in- 

 vesting which I have not been able to satisfy myself that I 

 have seen a ' Primordial utricle,' groAv gradually coarser in 

 texture by a process of differentiation of the mass in such a 

 Avay that granules appear Avhich increase in dimensions at 

 the expense of the surrounding and investing substance, 

 until the whole cell is filled Avith a coarsely granulated mass, 

 differing little in colour from the ori-iinal cell-contents. At 

 the same time the whole green mass recedes somewhat from 

 the enclosing cellulose Avail, and instead of rilling it completely 

 withdraws itself in such a Avay that its outline, near the ends. 



