68 



CORALS AND CORAL LSLANDS. 



3. Pennatnla tribe, or Pennatulacea. These are com- 

 pound Alcyonoids, that, instead of being attached to rocks 

 or some firm support, have the base or lower extremity free 

 from polyps and buried in the sand or mud of the sea-bottom, 

 or else live a floating life in the ocean. Their forms are very 

 various. 



In the Veretillum family (Veretillidae) they are stout and 

 short club-shape. One of the species from Hong Kong is 



C01'H()I5K1.E.MN()X t I.AVATf.M, V. , AND VERETII.LI;M STIMl'SONI, V 



shown in the figure on the left, with its polyps fully expanded, 

 and the small figure represents one of the polyps enlarged. 

 The third figure represents a polyp of another species, from 

 Hong Kong, a true ^'eretillum, enlarged three diameters ; the 

 specimens, obtained by Dr. Stimpson, and described by Prof. 



