5 8 4 



THE POPULAR SCIENCE MONTHLY. 



stomach is called the pyloric end, and it is made inside like a sieve or 

 strainer. The sides are stuffed out in the centre like cushions, and 

 quite covered with hairs (Fig. 25). Let us see why. Pylorus means 

 gate-keeper. It protects or guards the intestine from all intruders, 



Tail-fin, or Telson 



Nerve Bunch, or 

 Ganglion. 



Intestine. . . - 



Aorta 



Heart 



Blood Tubes (Arteries) 

 Gate-keeper (Pylorus), 



Meat-pipe (^Esophagus), 



Mouth 



Green Gland 



Eye. 

 Beak. 



Little Swimmers, 

 or SwinimereLs. 



Great Pineer. 



Fig. 22. 



such as big pieces of meat and hard bodies. None but the finest parti- 

 cles can pass through the strainer, and hence this pylorus is a very good 

 gate-keeper. The intestine does not go wandering about in the body 

 like the mussel's, but passes straight back (Fig. 22), and ends at the 



