68 



OUR COMMON BRITISH FOSSILS. 



The intervening spaces in the branched or arbore- 

 scent corals, between where one flower-like calyx is 

 seen and another, is called the coenenchyma. They 

 are the equivalents of the "inter-nodal spaces," or 

 distances which separate leaves from one another, in 

 the branches of a tree. It is the rapid porous growth 

 of these parts which enable such compound corals to 



.isij-ccafavcsa, a recent East Indian Coral. 



Stand against a good deal of marine wear-and-tear. It 

 is these parts, also, which bind the various corallites 

 together into one colony. In deep-sea corals this 

 coenenchyma rarely exists as a means of rendering 

 them compound, but a different method of "com- 

 pounding" takes place. Oculina is said to be the 

 only large coral now found in northern seas ; but our 



