26 



HYDROZOA. 



Fig.^ 



neV 



Morphology of Hydrozoa : — a, Hydrid; b, Corynid; c, Sertu- 

 larid ; d, Calycophorid ; e, Physophorid ; /, Medusid ; g, Lucer- 

 narid; — ir, polypite; t, tentacles; k, ccenosarc; tt', hydro theca 

 or polype-cell; v, nectocalyx or swimming-bell; a, pneumatophore 

 or float; i^, umbrella. (These drawings are diagrammatic.) 



with a ' hydrorhiza,' or adherent disc, prehensile 

 * tentacles,' and organs of reproduction {fig, 4, a). 



