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 Poritidcc. 



Dendrophyllia ;7?wm, represented in Figs. 68, 69, and 70, is an elegant 

 madrepore of the Mediterranean. Its polypidom presents a very 



large 



stein with short 



ascending 



branches ; it often attains to about 



