PLATE XII. 

 [Proc. Wash. Acad. Sci., Vol. Ill, PL XXIII.] 



FIG. I. Halecium reversum Nutting. Part of colony, showing internodes and 

 hydrophores (enlarged). 



2. Single hydranth with hydrophore (enlarged). 



3. Halecium robustum Nutting. Tip of branch, showing expanded hy- 

 dranths (enlarged). 



4. Part of branch with soft parts removed to show the hydrophores (en- 

 larged). 



5. Single hydranth with its hydrophore (greatly enlarged). 



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