250 



PHYSIOGRAPHY. 



[chap. 



extracted from the sea-water in which the animal Hves; just 

 as the calcareous salts of the bones are extracted from the 

 milk, and deposited in those parts of the body which are 

 becoming bone, in a growing infant. The deposit converts 

 the base of the, polype into a solid cement, which fixes 

 the animal to the surface to which it is attached ; and, if 

 the polype goes on growing not merely in height, but in 

 breadth, while the process of calcification extends as it 



Fig. 70. — Caryopkyllia Smiihii, a coral-polype from the coast of Devonshire.' 



grows, the coral will necessarily assume the conical form 

 exhibited in Fig. 71. It will be understood that the deposit 

 of calcareous matter does not extend into the region of 

 the feelers, or into the inner sac, so that the formation 

 of the coral skeleton no more interferes with the per- 

 formance of the functions of the body in the polype, than 



'' From Mr. Gosse's NaturalisCs Rambles on the Devjnshire Coast, 

 1853. 



