224 



CORALLIUM. 



A TREE-LIKE, inarticulated Polypidom ; axe stony, 

 stiff, and susceptible of a beautiful polish ; rind 

 fleshy, becoming chalky and very friable by desicca- 

 tion, and adhering to the axe. 



The Coral is a Polypidom resembling a small tree 

 deprived of its leaves and twigs, having nothing left 

 but the trunk and branches ; it is fixed to rocks by a 

 large base, from which it rises to the height of three 

 decimetres. 



It is composed of a calcareous axe, and of a gela- 

 tino-cretaceous rind : the axe is equal to marble in 

 hardness ; it is formed by concentric layers, which 

 become perceptible by calcination ; its surface is 

 more or less striated, the striae are parallel, and un- 

 equal in depth. 



A reticulated body, formed of small membranes, 

 with numberless vessels and glands filled with a milky 

 juice, appears to unite the rind with the axe ; this re- 

 ticulated body is found in all corticiferous Polypi- 

 doms : the rind is of a less deep colour, of a soft sub- 

 stance, and formed of small membranes and slender 

 filaments ; it is pierced by tubes or vessels, and co- 

 vered with tubercles which are thinly scattered and 

 have a large base, the summit of which is terminated 

 by an opening divided into eight parts. In the interior 

 is found a cavity which contains a white and almost 

 transparent polypus. Its mouth is surrounded by 



