240 



CLASSIFICATION OF ANIMALS 



warmer seas where they often occur in vast numbers. Some 

 forms are widely distributed. To the Anthozoa, sponges and 

 sea weeds, is chiefly due the brilliant coloration so often found 

 in the sea bottom of tropical and sub-tropical seas. Most 

 anemones are attached to some firm object such as rocks, sea 



Fig. 136. — A whip coral (Gorgoniidae). X 1/2. 



weeds, shells or even the surface of other animals. This attach- 

 ment is effected by a sucking action of the basal disc and permits 

 the animal to move by a slow creeping motion. Some anemones 

 lie partly embedded in the sand into which they can completely 

 withdraw by longitudinal contraction. Others form a leathery 



