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. 



Cory ne. 

 Capitate with free medusae. 



Syncoryne. 

 C. Parasitic on Seriola zonata (osseous fish). 



Hydrichthys. 



No tentacles, two kinds of individuals. Hydroid reduced 

 to a botryoidal cluster of medusae. 



Tkecaphora. 



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 ccenosarc. 



Ophiodes. 

 Without tentacular organs over the ccenosarc. 



Halecium. 



II. Calycles bell-shaped. 



a. Operctilatcd Lovenella. 



6. Non-operculatetl. 



Clytia. 



Obelia. 



Campanularia. 



Thaumantias. 



Gonothynea. 



'Cup-like structures, hydrothecie, in which the hydranths are protected. 



