THE HYDROMEDUSAE 



a' 



Fin. 46. 



OL 



Fin. 45. 



jr 



45. Physophora hydrostatica. a, stem or conn of the colony ; a', pnetimatophore (air- 

 bladder) ; m, nectophore ; o, orifice formed by the margin of the umbrella ; t, hydrophyllia ; n, 



laeckel.) 



47. Diagram of the structure of an Ersaeome (free monogastric generation of a Diphyid). 

 , gastrozooid ; H, hydropliylliuni ; .17, sexual medusoids ; A', nectophore ; OL, oleocyst ; 

 '. tentacle of crastrozooid. (Modified from Haeckel.) 



(7, garoo , , 



T, tentacle of gastrozooid. (Modified from Haeckel.) 



17 



