PLATE IX. 

 [Proc. Wash. Acad. Sci., Vol. Ill, PI. XX.] 



FIG. i. Obelia dubia Nutting. Part of colony (enlarged). 



2. Gonothyrcea inornata Nutting. Part of colony, showing hydrothecse 



and gonangium (enlarged). 

 3 and 4. Gonangia (enlarged). 



(222) 



