STAR-FISHES AND SEA-URCHINS. 51 



aperture. That aperture is the mouth, and it opens, 

 like the mouth in Sea-Anemones or Jelly- Fishes, into 

 a cavity which is the stomach. From that cavity, 

 tubes run up each of the arms to its extremity, so that 

 the food, passing from the stomach into these tubes, 

 can circulate through the whole body. They have a 

 very singular way of obtaining their food. They have 

 no long tentacles like the Sea-Anemone to catch their 

 prey, but they turn the stomach out over the food, en- 

 veloping it in this way ; and having so secured it, they 

 turn it back again. On the lower side of the Star- Fish, 

 arranged along the centre of each ray or arm, there are 

 a number of small appendages that look like short feel- 

 ers ; they are almost constantly in motion ; and if you 

 look at them closely, you will see that the end of each 

 one spreads very slightly into a club-shaped extremity, 

 and has a small depression, forming a little pit. These 

 are their organs of locomotion ; they are suckers, and 

 are so constructed as to cling closely to any surface they 

 touch. When the Star- Fish wants to move, he stretches 

 one of his arms in the direction in which he means to 

 go, and attaching his suckers to a rock or sea-weed, or 

 any object near him, he drags himself along. You 

 know, when you are climbing a tree, and you come to 

 a part of it where there is no branch upon which you 

 can fix your foot to take the next step, you may stretch 

 your arms to some higher bough, and draw the rest of 

 your body up in that way. This is not unlike the Star- 

 Fish's way of moving ; he turns one of his rays in the 

 right direction, stretches his suckers as far as he can, 

 adheres by them closely to the surface along which he 

 is moving, and drags the rest of his body on by the 



