CORALS. 247 



perform the part of the skeleton in the human 

 frame. This central internal support is usually 

 denominated the axis. The fleshy mass, or cover- 

 ing, possesses sensation, and is ramified by various 

 tubes and canals for the sustenance and other vital 

 functions of the polypi. The Asteroida are fre- 

 quently thrown on the sea-shore, and when dried 

 by the sun the skeleton weighs but a few grains. 



Allied to the Turlinolia and Caryophyllia are the 

 Fungia, or sea-mushrooms. These elegant forms are 

 found in a great variety ; the corals are white, of a 

 flattened, round shape, made up of thin plates or 

 scales, around which is a translucent, jelly-like sub- 

 stance, and amidst it a large polype; for, unlike 

 others, they exist as individuals ; the lower part is of 

 a strong nature, by which the animal is affixed to the 

 rock whereon it lives. 



Another very abundant coral around our islands is 

 the Brainstone coral, or Meandrina cerebriformis, — 

 so named from its surface resembling the convolu- 

 tions of the medullary matter in the human brain. It 

 attaches itself by a strong stony secretion to rocks. 



Gorgonia. — The Gorgonice are found widely diffused 

 around the reefs of Bermuda ; they appear to dwell 

 usually in deep water; when observed in shallow 

 water, their colours are richer, deeper, and brighter. 



