70 



Veit Brecher Wittrock. 



lateral process belonging to the supporting cell, which circumstance is occasioned 

 by the fact that the transversal cell-wall, which has separated the branch process 

 first formed from its mother cell, has been formed somewhat higher up in the branch 

 process, not at its base. *) The top branches are often bent like a sickle. The 

 thickness of the cells varies between 85 and 125 fx. Their length is 7 — 25 times 

 greater than the thickness. 



According to D:r Grunow's opinion, directly communicated to me, boih the 

 forms now mentioned belong to Cladqphora sumatrana v. Mart. (i. e. to Pithophora 

 sumatrcma (v. Mart.) nob.) The one growing in brackish water D:r Grunow has 

 determined as being a variety under the name of fusccscens. My opinion is also 

 that these forms are nearly related to P. sumatrana (v. Mart.) nob. Whether 

 they are quite identical with it can not be determined Avith certainty till they are 

 known in a fertile state. The form grown in fresh water calls to mind P. cequalis 

 nob. almost more than P. sumatrana (v. Mart.) nob. 



x ) The same circumstance sometimes takes place in P. polymorphs nob.; see pi. 1, 

 figs. 15 and 17. 



