THE OCEAN WORLD. 
1 02 
The perforated Zoautharia form three very natural families : the 
Eupsa.mm.idse, the Mad.reporidie, and the Poritidm. The first have 
the solid pai'ts of the polypes, simple or complex, with well-developed 
lamellar portions, the central column spongiose, walls granular, semi- 
ribbed, and perforated. The second are composite, increasing by 
gemmation ; walls spongy and porous ; septa lamellous, and well- 
Fig. 74. Pendrupbyllia ramoa, half natural size (lie Hlainville). 
developed. In the third the visceral chambers are divided into two 
equal parts by the principal septa, which are more developed than the 
others, meeting by their inner edge. The Dandrophyllim (Fig. 74) 
are conspicuous .among the Eupsammidse. 
We shall describe three genera, the two first of which belong to the 
Madrepokjea, and the last to the family of the Porides. 
Dendrophyllia ramea, represented in Figs. 75 and 76, is an elegant 
