184 ZOOPHYTES. 



IV. The contents consist of five or six corpuscula, — globular in an 

 early stage, but in a later, relaxing into planulae, which escape by the 

 orifice. 



V. The planulse endowed with the power of expeditious motion, lose 

 their natural configuration, and contracting in a circular spot, become 

 stationary. 



VI. A spine rising from the spot, enlarges as a cell at the summit, 

 whence a hydra is displayed, proving the young Sertularia. 



Plate XXXIII. Sertularia (Plumularia) falcata. 



Plate XXXIV. 



Fig. 1. Extremity of a branch with hydrse. 



2. Branch bearing vesicles, slightly enlarged. 



3. Vesicle with white corpuscula. 



4. Vesicles with yellow corpuscula. 



5. Vesicles with yellow corpuscula. 



6. Vesicles with yellow corpuscula, relaxing in planulae ; one escaping 



from the orifice. 



7. Yellow planulse from the vesicles. 



8. Yellow planulse from the vesicles losing their proper form. 



9. Yellow pianulse approaching incipient metamorphosis. 

 10. White planula from the vesicle, fig. 3. 



11-14. Diffusing root from four metamorphosing pianulse. 



15. Originating stem from a diffusing root. 



16. Stem bearing two buds. 



17 18. Stems with two cells ; partition of the roots disappearing. 



19. Young Sertularia with a hydra and two cells yet untenanted ; arti- 



culations indenting the stem. 



20. The same more enlarged. 



21. Young specimen with three hydrae, the stem articulated. 



22. The same more enlarged. 



23-27. Young specimens of varied configuration. 



All the preceding figures are enlarged. 



