GORGONIN^. 



221 



sustains the first, and is called the axis. This axis presents a horny 

 appearance, and was formerly believed to possess chemical characters 

 analogous to the horns and hoofs of some of the vertebrated animals. 

 It has recently been asserted that the tissues of these corals consist 





Fig. 79. — Fan Gorgon, magnified. 



essentially of a particular substance which resembles horn, but which 

 is called Corneine. A little carbonate of lime is sometimes found 

 united with this substance, but never in a sufficient quantity to give 

 it a stony consistence. The outer covering developes itself in con- 

 centric layers, between the portion of the axis previously formed and 

 the internal surface of the basic covering. 



