484 



to be quite normal. Intermixed with Ihese cell-filaments consisting 

 of one row of cells, occur some filaments in which the cells are 

 divided into two rows (Schizogonium-stage fig. 99, n), and this division 

 is continued on the same plane so that it forms a complete plate 

 (Prasiola - stage fig. 99, b and f). These piates are sometimes fa hiv 

 broad mnch more so than fig. 99, /", but piates, as large as those oc- 

 curring in the land -form of Prasiola crispa, were not met with. I 

 have only observed these Prasiola-like cell- piates in the material 

 from Hojvig, in which there further occurred some filaments re- 

 sembling the fragment illustrated in fig. 99, a. As may be seen from 

 this figure, the cells have become divided in more than two direc- 

 tions, thereby reminding one of the genus Gayella fonnded by 

 Rosen vinge. Typically developed Gayella -specimens did not 

 occnr in this gathering, consequently, it was very interesting that 

 a gathering from S vin 6 contained some well -developed Gayella- 

 filaments exactly agreeing with Rosenvinge's description. Fig. 99, d, 

 shows a filament which has begnn to develop into Gayella, the 

 cells being divided in more than two directions; and fig. 99, o, p 

 show the transverse seclion of thinner Gayella- filaments. In the 

 latter gathering there also occurred cell -filaments exactly agreeing 

 with, e. g. fig. 99, e; and fig. 99, h represents a fragment of such a fila- 

 ment bearing one rhizoid. Finally in fig. 99, / and m are shown 

 two fragments of filaments whence proceed several rhizoids side by 

 side, corresponding with Rosenvinge's fig. 45, G. 



It is on account of the interesting way in which the filaments 

 consisting of a single row of cells pass by such very gradual stages, 

 on the one hånd into the form Prasiola, and on the other into the 

 form Gayella, that it appears to me to be impracticable to maintain 

 the genus Gayella; the latter must therefore be regarded only as a 

 phase in the development of Prasiola crispa subspec. marina eo- 

 ordinately with the already accepted Ulothri.v radicans- stage and 

 Schizogonium-P/asiola - stage. 



With regard to the contents of the cells, the star-like chromato- 

 phores, etc, they exactly agreed with G av s's description in »Algues 

 vertes« (pp. 80— 86) and Wille's (1. c). 



In »Deuxieme Mémoire sur les Algues marines du Groenland« 

 (p. 116), Rosen vinge points out the following characterislic of 

 Gayella: — »Les couches intérieures des membranes qui entourent 

 les cellules, donnent la reaction de cellulose avec la chlorojodure 

 de zinc, la membrane épaisse extérieure des filaments reste au con- 



