214 M, c. cooke's notes on vaucheria. 



manner to the previously examined thread. The whole gathering 

 showed a great preponderance of septate filaments, divided com- 

 pletely, and somewhat constricted at the joints, some of the cells 

 being two and others three times, or more, the diameter in length. 

 Filaments which did not bear Oogonia, or only one or two, being 

 most divided. Approaching the subject with a strong feeling ad- 

 verse to the production of veritable septa, every precaution was 

 taken, I think, to prevent any misinterpretation, and I was com- 

 pelled against my first impression to accept the fact that the fila- 

 ments of this undoubted Vaucheria had become divided off into 

 cells, at the period of fructification. 



The appearance of these cells, in some sense differed from con- 

 tinuous threads, in that the plasma was collected towards one end, 

 or the centre of the cells, and in many instances was dense, ap- 

 parently mingled with oval bodies as if undergoing, or had under- 

 gone, differentiation. It must be stated that the filaments were 

 very much coated with small Diatomacece and other minute Alga3, 

 so that the view was obstructed. 



The question which at once suggested itself was, as to the 

 object of this septation. And here it may be suggested that the 

 single asexual zoospore, produced in small numbers, and the single 

 oospore produced in the oogonia always had appeared to be a very 

 sparse provision for the reproduction of the species, as compared 

 with the large number of zoogonidia, which are produced in every 

 fertile cell of Cladophora and Chcetomorpha. Even in the 

 BotrTjdiacea, the multiplex modes of reproduction are strongly in 

 contrast with what has been known as the reproductive process in 

 Vaucheria. For these reasons there does not appear to be any im- 

 probability in the supposition that zoogonidia may be produced in 

 Vaucheria in cells, divided off for that purpose. The formation of 

 the cells, the accumulation of the cytioplasm, acquiring density, 

 and as I strongly believe, differentiation lend strength to the prob- 

 ability that reproduction by zoogonidia may yet be discovered in 

 Vaucheria. We failed, both Mr. Bates and myself, to detect any 

 active zoogonidia, but we have both seen bodies of a definite form, 

 resembling zoogonidia at rest, in the cells, and in the water in 

 which the gathering was kept were found similar bodies outside the 

 threads, some in a state of germination. It must not be supposed 

 that we affirm, or have direct evidence to affirm either that 

 zoogonidia are produced in the cells, or that the free germinating 



