PLATE I. 



Figs. 1-4. — Plwnularia fiabelluni. 

 Fig. 1. — Natural size. 



Fig. 2. — Portion of a liydrocladium magnified ; lateral view. 

 Fig. 3. — Same ; front view. 

 Fig. 4. — Portion of branch, with origin of hydrocladia. 



Figs. 5, 6. — Plumularia laxa. 



Fig. 5. — ^Natural size. 



Fig. 6. — Portion of hydrocladium giving origin to a secondary bydrotheca-bearing ramu- 

 lus ; magnified. 



Figs. 7, 8. — Plumularia dolichotheca. 

 Fig. 7. — Natural size. 

 Fig. 8. — Portion of hydrocladium ; magnified. 



