HABITS OF THE NORTHERN SEA-STAR. 203 



When inactive, the animal is greatly contracted, 

 crouching closely in some cavity, as if for conceal- 

 ment, or occupying a corner of the tank, apparently 

 quite helpless and incapable of resistance. When 

 roused, however, by heat or hunger, it advances as 

 if half- swimming, with a quickness such as could 

 scarcely be ascribed to its nature, its rays extended, 

 and the numerous suckers in action. It never really 

 swims, nor does it spontaneously leave the water, 

 though frequently met with left behind by the re- 

 ceding tide. 



No creature is more rapacious. Its prey is de- 

 voured alive whenever it can be overpowered. Let a 

 moderate-sized mussel be presented, and it is straight- 

 way covered by the body of the Star-fish, while, the 

 rays closing around it, the animal sustains itself on 

 them as on feet, contracting more and more as the 

 food is gradually swallowed. If the portion of food 

 be too large for the mouth, the stomach begins to 

 protrude, and is applied around it. In this way 

 shell-fishes, whether univalves or bivalves, become an 

 easy prey : the Turbo and the Pholas fall victims 

 alike. As the prey is brought under the mouth, it is 

 hemmed in on all sides by the rays, and either crushed 

 asunder or swallowed entire : small fishes, small 

 Echini, and even some of its own race, are all sacri- 

 ficed to its merciless voracity. 



Though much exceeding the specific gravity of the 

 water, Star-fishes of various kinds are capable of a 

 swift, gliding motion, as if nearly buoyant a circum- 

 stance that may be accounted for by a quantity of the 

 surrounding element being absorbed into their inte- 



