CORAL-MAKING ACTINOID POLYPS. 53 
to the fact that only the lower parts of the polyp secrete coral, 
as a moment's consideration will make apparent. 
In other cases, the budding cluster is small, and hence 

PORITES MORDAX, D. 
makes small branches, as in the annexed figure of a species of 
Porites, from the Feejees. The cells in this genus are very 
small and nearly or quite superficial, as the figure shows. 
