SUBDIVISIONS OF ACTINOID POLYPS. 79 
of the larger kinds of simple corals, such as those of the gen- 
era Zaphrentis and Heliophyllum, had at times a diameter of 

PORITES LEVIS, D. 
three or four inches, so that the breadth of the polyp flower 
was probably at least six inches. Hemispherical masses of 
