30 CCELENTERATA AND 



b. Tentacles of two kinds. 



Upper, capitate; lower, rigid in single 

 verticils . . . . . Cladonema. 



Upper, capitate ; lower, filiform in sev- 

 eral verticils . . . Stauridium. 



c. Tentacles in several whorls. 



Capitate without free medusae. 



Coryne. 

 Capitate with free medusae. 



Syncoryne. 

 C. Parasitic on Seriola zonata (osseous fish). 



Hydrichthys. 



No tentacles, two kinds of individuals. Hydroicl reduced 

 to a botryoiclal cluster of medusa). 



Thecaphora. 



Hydroids with hydranth and sexual bodies enclosed in 

 a cup. 



A. Calycles 1 erect and free, hydranths retractile. 



I. Calycles supported on a short process from 



the stem ; hydranths partially retractile. 

 With tentacular organs over the coenosarc. 



Ophiodes. 



Without tentacular organs over the ccenosarc. 



Halecium. 



II. Calycles bell-shnped. 



a. Operculated Lovenella. 



b. Non-operculated. 



Clytia. 



Obelia. 



Campanularia. 



Thaumantias. 



Gonothyraaa. 



J Cui)-like structures, hydrothecae, in which the hydranths are protected. 



