Jellyfishes. 



39 



swimming bell in locomotion. This is seen in the 

 Portuguese Man of War (fig. 22), whose purple crested 

 air sac and long tentacles are well known to sailors, 

 as by their large thread-cells they inflict dangerous 

 stings on those who incautiously touch them. These 



FIG. 23. 



a 



Disk-bearing Jelly-fishes ; a, Rhizostoma ; b, Chrysaora. 



swimming and floating colonial Hydroids are called 

 Siphon-bearers (Sifhonophora). 



Sub-Class 3 : Discophora. The large Jellyfishes 

 whose translucent bodies are so often thrown on the 

 shore by the receding tides, are the representatives of 

 a sub-class characterised by possessing single polypites 



