620 



THE WONDERS OF GEOLOGY. 



Lect. VJ. 



and a view of an expanded polype of the same seen from 

 above, in Jig. 6; the polype of another species of Tubipore 

 is represented in Jig. 12. 



20. Madrepora. — In the Red Coral, no cells are 

 formed by the hard skeleton to serve as a protection for the 

 polypes ; but in the family of branched, or arborescent 

 calcareous polyparia, called Madrepores, the little cups 

 or cells, with radiating lamellae, in which the polypes are 



2 3 



Lign. 136. — Recent corals. 



Fig. 1. A branch of Oculina ramca. 2. A branch of Madrepora muricata. 3. A 



branch of Isis hippuris : a, the cortical substance covered with pores, which are 



the cells of polypes ; 6, a branch deprived of its outer covering, and exposing the 



articulated axis or stem. 



situated, are composed of the same substance as the 

 axis. When the animals die, and the outer fleshy investment 

 perishes, the coral is therefore found to be studded over with 

 elegant, lamellated, stellular cells, variously formed and 

 arranged in the different genera and species. In some the 

 cells are very distinct ; as in a Mediterranean species, the 

 May-blossom Coral (Oculina ramea, Lign. 136, Jig. 1) ; in 

 others they are exceedingly minute, as in this common 

 Madrepore (M. muricata, Lign. 136, Jig. 2), from the 

 West Indies. The white branched corals so numerous in 

 collections belong for the most part to this group. 



