PLATE VI. 



Fig. 1. Dipliasia clarce. Portion of colony sliowing branching and hydro- 

 thecal arrangement. 



2. SerUdarella conica. Number of colonies showing earliest stages 



of development. 



3. Single gonophore growing from the stolon. 



4. Portion of hydrotheea to show four-parted operculum. 



5. Sertularia furcata. Portion of colony to show mode of attachment 



to the stolon and the arrangement of the hydrothecae. 



