EXPLANATION TO PLATE IV. 



FIG. 1. ftertiilnrin, roriiiriiiri (MoCready). Colony with gonangia ami expanded hydranths. Drawn from life 

 (enlarged). 



2. Sertularia cornieina. Pair of hydrothec4i- (greatly enlarged). 



3. Rrrliiluriii /'uniiriiiii. (lonangium (enlarged). 



4. fli'i-liiliirin riiniiciim. Side view of colony with parasitic rampanularian and its gonaiigium (enlartred). 



5. Sertularia cornicina. Part of same colony (enlarged). 



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