HYDROZOA. 



81 



Class 

 HYDROZOA. 



I 



/ 



No umbrella. 



An umbrella. 



r 



An hydrorliiza. 



No hydrorbiza. 

 Oceanic. 



Locomotive. 

 Inhabiting fresh-water. 



Order I. 

 Hydride. 



Fixed. 



No hydrothecse. 

 Order II. 



CORTNTD^. 



Hydrothecse. 



Order III. 

 Sebtularid^. 



r 



Polypites free from nectocalyces. 



Polypite sus- 

 pended from 

 the roof of a 

 nectocalj'x. 



No pneumatophore, 

 Nectocalyces. 

 A Somatocyst. 



Order IV. 



CALYCOPHORIDiE. 



A pneumatophore. 



Nectocalyces 

 present or absent. 



Order V. 

 Physophobidje. 



Order VI. 



MEDUSmiB. 



a 



Order VII. 



LUCERNAEIDJI. 



