CORALS. 



5i5 



with them. The different kinds of these particles, found in different species, are of 

 great importance in classification. One of the most common of the group is 

 Gorgonia verrucosa, found in the Mediterranean, and here illustrated. A 

 shark's egg is shown in the illustration attached to the coral by means of its 



a sea-fan (Gorgonia verrucosa), with a shark's egg fixed to its branches (nat. size). 



appendages. The soft covering of this Gorgonia is white. These animals occupy 

 no very important place in the economy of nature ; but several gastropods seem to 

 attack the polyps, and brittle-stars climb up the branches in search of food. A 

 beautiful form is Isidigorgia, resembling a corkscrew with a long spiral. It sends 

 off at right angles to the principal axis, and at short intervals, delicate branches, 



