PLATE XXI. 



Fig. 1. Rhipidigorgia flabellum Valenciennes, reduced about one half. 



Fig. 2, 4. Rhipidigorgia flabellum Valenciennes, magnified portions, showing the polyp-cells empty 

 and dried. 



Fig. 5. Rhipidigorgia flabellum Valenciennes, a planula, magnified (?). (No explanation of this figm-e 

 could be found.) 



Fig. 6. Rhipidigorgia flabellum Valenciennes, a small portion of the coralluni, natural size, with partly 

 expanded polyps. 



Fig. 7. Rhipidigorgia flabeUum Valenciennes, branchlet partly denuded of its cortical portion, and show- 

 ing the horny axis. 



