m 



c. H. OSTENFELD. 



Ch. crinitum Schutt. 



Valves with rounded 

 angles, not touching one 

 another, a little constric- 

 ted at the sutures. 



Foramina very narrow, 

 constricted in the middle. 



Awns issue fromalittle 

 within the angles of the 

 valves. 



Terminal awns short, 

 forming a sigmoid curve 

 at the basal part, then 

 nearly parallel. 



Ch, pseudocrinitum Ostf. 



Valves with sharp ang- 

 les, touching one another, 

 rather deeply constricted 

 at the sutures. 



Foramina narrow, some 

 times a little constricted in 

 the middle. 



Avns is s sue from the 

 angles of the valves. 



Terminal awns not shor- 

 ter than the other, forming 

 a large, evenly bended 

 curve. 



Trykt den 30. Sept. 1901. 



