HYDROIDS. 235 



do not hatch medusae like the parent, but each hatches a 

 little hydroid which is first free, then afterwards becomes 

 attached to a shell, sea-weed, or stone, and from this 



Fig. 484. Portuguese Man-of-War. 



little hydroid others branch till a little community of 

 hydroids has grown up, as in Figure 478. From these 

 hydroids bud again the Coryne, Figure 479. 



In some kinds, as Tubularia, Figure 481, the hydroid 



