THE POLYPIERS. 83 
same polypier, the Gerardia Lamarckit. This shows the unsettled 
state of affairs. Under the general term Polypier are included dis- 
tinct groups of animals, some constructed upon the type of the 
AN HYDRARIA, 
(Sertularia ramea.) 
Hydra, others upon that of the Actinaria; a third, like the Plumu- 
laria, follow a totally different plan of organisation. The first of 
these are the Polypier hydraria, the second the Polypier actinaria, 
and to the last belong many classes of animals. 
G 2 
