PLATE XV. 

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



FIG. i. Thuiaria coei Nutting. Part of branch, showing hydrothecae and 

 gonangia (enlarged). 



2. Lateral view of hydrotheca (enlarged). 



3. Single gonangium (enlarged). 



4. Thuiaria costata Nutting. Part of main stem, showing origin of 

 branches (enlarged). 



5. Front view of terminal branches (enlarged). 



6. Two pairs of hydrothecse (greatly enlarged). 



7. 8, 9. Gonangia (enlarged). 



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