POLYZOAN CORALS 169 



Cellepora is not the only genus in which these lumps of 

 coral of irregular shape are formed by the overgrowth of 

 successive laminae of zooecia. Lumps of Polyzoa 3 or 4 

 inches in diameter formed by the zooecia of the genera 

 Microporella and Schizoporella are not infrequently found. 



These can be distinguished roughly from the more 

 abundant Cellepora by the smaller size of the zooecia. 



It is difficult to give, without going into detailed account 



Fig. 81. — Cellepora. From oft .\ucklaiid, New Zealand. Xat. size. 



of Polyzoan structure, the precise characters by which these 

 genera are distinguished from one another by the special 

 workers in this group, but as Cellepora is such a widespread 

 genus it may be of interest to state the characters which 

 serve as a guide to its recognition. 



The zooecia of Cellepora are described as flagon-shaped 

 (urceolate) and erect, the end of the zooecium which bears 

 the orifice projecting from the surface, while the base is 

 more or less submerged. The size of the zooecia varies a 



