PHYLUM CCELENTERATA 



I07 



hfift 



Fig. 50 — Halistemma tergestinum. A, the entire colony; B, a* single group of 

 zooids; cae, ccenosarc; dz, dactylozooid; kph, hydrophyllium or bract; net, 

 nectocalyx or swimming-bell; ntc. battery of nematocysts; fi, polype; /«, 

 pneumatophore or float; s, s', sporocysts; /, tentacle. (After Claus.) 



