G. SERTULARIA. 85 



compressed ; ovaria nearly of an oval form, and bor- 

 dered; branches dichotomous, and in rows. 

 European seas. 



CYPRESS-FORMED. 



17. Sertularia cupresso'ides. Cells scarcely pro- 

 jecting, simple, and obliquely truncated; vesicles oval; 

 branches dichotomous, articulated, and dispersed. 



White sea. 



MISENIAN. 



18. Sertularia Misenensis. Very branching, and 

 dichotomous ; cells alternate, small, and diverging ; 

 ovaria oval, pedunculated, and axillary. 



Mediterranean, near Misena. 



LICHEN. 



19. Sertularia lichenastrum. Stem pinnated 

 and articulated ; cells imbricated in two rows. 



European seas. 



clustered. 



20. Sertularia racemosa. Stem upright, cylin- 

 drical, and branching ; branches almost arched ; cells 

 dispersed ; ovaria branching. 



Mediterranean. 



dusky. 



21. Sertularia. fusee scens. Cells nearly opposite, 

 and tubular ; ovaria approximate, small, and with 

 three tubercles. 



Coast of Cornwall. 



SPIKED. 



22. Sertularia spicata. Stem tubular, panicled, 

 and marked with rings ; branches very close, verticil- 



