10 



LESSON ON STAR-FISH. 



which have what is called the sixth sense with which they perceive a boat 

 .passing over them. If you put your hand in the water they perceive that, 

 too. 



At the end of each ray is an eye-speck, though they are so small that 

 they cannot be called eyes. They are not of much use, and people think they 

 cannot see much with them. They are surrounded by spines like the daisy 

 is by petals. The nerves go around the body and a single nerve extends 

 into the end of each ray to the eye-specks. 



The star-fish breathes the air that is in the water. The water is taken 

 in through the strainer and then it goes down the stone canal, so called be- 

 cause it always has sand in it. From the stone canal it goes into the water 

 tube that passes around the body, then into each ray. When the star-fish 

 wants to let the water out he lets it out through his feet. 



Figure 8, 



Figure 



mm 



Diagram of lower side of star-fish, show- 

 ing stomach protruding and position of 

 mouth. 



A, water system of star-fish. S, strainer, 

 H, heart, I, II, III, IV, V, rays, W, circle 

 about mouth. B, young star-fish, C, spines 

 I, spine, II, tentacles, III, snappers. 



At the right of the stone canal is the heart. The blood vessels extend 

 from the heart around the body, and lie beside of the water tube, and the 

 air passes through the water tube from the water into the blood-vessels. 



On the under surface of the rays are grooves ; in the grooves are the 

 feet. When they want to protect their feet, they draw them up into the 

 grooves. It looks as if there were two rows of feet on each side of the 

 grooves, but there is only one row arranged zig-zag. The feet have suction; 

 when the fish wants to cling to a rock, she puts her feet on the rock and 

 draws the water back into the bulbs at tops of the feet. This makes a 

 vacuum. The mouth is on the under side, in the middle of the body and 

 is protected by ten spines which can close it. 



