164 



ZOOLOGY 



sometimes several feet in length and containing batteries of 

 stinging-capsules powerful enough to sting the hand as severely 

 as a nettle. The male reproductive zooid remains attached, as in 



C?' 



FIG. 122. Fhysalia : the living animal floating on the surface of the sea. cr. crest ; p. polype 

 pn. pneumatophore ; t. tentacle. (After Huxley.) 



Halistemma, but the female apparently becomes detached as a 

 free medusa. 



In DipJiycs the float is absent. Two swimming-bells (Fig. 123^4, m) 

 of proportionally immense size are situated at the proximal end 

 of the ccensarc, and are followed by widely-separated groups of 

 zooids (B}, each group containing a polype (ri) with its tentacles (i), 



