MEMBRANIPORID^. 29 



to the Marginaria of Roemer, some may perhaps be regarded as representing the raucli- 

 worn remains either of other species of Memhranipora or of Lepralia, in which only the 

 outline, as it were, of the adherent cells is left. 



SYNOPSIS OF SPECIES, 

 (a) Cells more or less open in front ; usually no posterior calcareous wall. 



a. Inarmatce. 



1. M. TUBERCULATA. 



2. M. MONOSTACHYS. 



3. M. Savabtii, 



4. M. elegans. 



5. M. DUBIA. 



/3. ArmatcB. (Furnished with avicularia.) 



6. M. TRIFOLIUM. 



7. M. POUILLETII. 



8. M. RYNCHOTA. 



9. M. APERTA. 



(i) Cells closed in front by a calcareous lamina ; posterior wall calcareous. 

 a. Inarmatce. 



10. M. OBLONGA. 



11. M. BIDENS. 



12. M. ANDEGAVENSIS. 



13. M. FISSURATA. 



/3. Armatce. 



14. M. OCEANI. 



15. M. HOLOSTOMA. 



