Fig. 10. Part of a colony of Hydractinia. dz, dactylozooid (defensive 

 person) ; gz, gastrozooid (nutritive person) ; &, blastostyle 

 (asexual reproductive person); gon, gonophores (sexual repro- 

 ductive persons) ; rh, hydrorhiza (creeping stolon). (Magnified.) 

 (After Allman.) 



