22 



CCELENTERATA AND 



4. H. 



Willia. Bell disk-like with small clusters of lasso-cells 

 at intervals on the external walls. Tubes branched, four 

 at origin from the proboscis. 



W. ornata. 

 A. III. 



Mabella. Bell globose. Tubes eight. Tentacles 

 numerous, short, flexible. Proboscis small with lateral 

 buds. 



M. gracilis. 



Melicerlum. Bell oval, tall, mitre-shaped. Tubes 

 eight. Tentacles numerous, long and very flexible. Pro- 

 boscis with complicated lips. Tubes with ovaries along 



their whole length. 



M. campanula. 



MELICERTOM. 



'. I, a. 



Obelia. Body disk-shaped, transparent, colorless. 

 Sense-capsules with numerous otoliths, arranged at irreg- 

 ular intervals about the bell rim. Numerous rigid tenta- 

 cles. Four tubes. Ovaries spherical, pendent from the 

 tubes. The bell o ten reversed, and turned in such a 



