136 



BOYS AND GIRLS IN BIOLOGY. 



are of no use to the lobster, are sent out again by the 

 wide mouth of the stomach. It is very interesting to 

 know that there is hardly a machine that man has in- 

 vented, but something like it, though usually much bet- 

 ter, may be found in some animal. The lobster's 

 stomach is a perfect machine for grinding and straining, 

 and it will repay all your trouble if you take a peep at 

 it in the lobster itself. When you begin to look for 

 the stomach you must go to the head instead of the 

 body, or abdomen. Why the lobster should have such 

 a perfect mill and strainer is at first hard to under- 

 stand, because he is not at all particular or dainty as to 

 his food ; he is a regular scavenger, and feeds upon all 

 sorts of refuse and carrion. But the little gate-keeper 

 (pylorus) opens the way into a very thin, delicate 

 tube — the intestine, and, on account of the extreme 

 fineness of its walls, it is of the greatest importance 

 that the gate-keeper prevent any of the coarse abomi- 

 nations on which the lobster feeds from entering the 

 intestine ; hence you see the necessity of the mill and 

 strainer. The intestine does not go wandering about 

 in the body like the mussel's, but passes straight back 

 (Fig. 116) and ends at the anus,* on the under part of 

 the tail-piece (telson). On each side of the head breast- 

 plate (ceph alo-thor ax) lies a long, soft, yellowish, 

 green mass. This is the liver, and it opens into the 



