26 



IS. I ii aqua mariiia et sunmarina. 



a. Septis 2. 

 81. Grammatophora: (a. b. marina; c. serpentina). 



Frustula per isthmum concatenata (a) latere tabulata rectangula , vittis 



duabus varie undulatis (c) medio interruptis instructa ; (b) a fronte ob- 



longo-lanceolata , nodulo centrali nulio. 





