MADREPORES. 



185 



polyps simple or complex, with well-developed lamellar portions, the 

 central column spongious, walls granular, semi-ribbed, and perforated ; 

 the second have a reticulated sclerenchyma, septa more or less dis- 

 tinct, the visceral chambers containing sometimes small rudimentary 

 plates. 



Fig. 68. Dendrophyllia ramea, half natural size De Blainville). 



We shall describe three genera, the two first of which belong to 

 the Madreporince., and the last to the family of the Poritida. 



Dendrophyllia ramea, represented in Figs. 68, 69, and 70, is an elegant 

 madrepore of the Mediterranean. Its polypidom presents a very 

 large stem with short ascending branches ; it often attains to about 



