Xx. CRAYFISHES. . 291 



fresh fish. I have just given one of mine, which I knew 

 must be hungry, a piece of fish, letting it down gently 

 into the water so that it touched one of his legs. He took 

 no notice for a minute or two and then his feelerets began 

 nicking up and down. These organs are the seat of a 

 sense of smell or taste, it is difficult to know which to call 

 it, which advises the crayfish of something eatable in the 

 water. Then he turned round and began poking about 

 with the long feelers till he found the piece of fish. 

 Having found out its whereabouts, he walked over it and 

 seized it in the pincers of the front pair of legs. 



My bowl-shaped tank has glass sides and is so placed 

 that I can watch my crayfish from below. Looking up at 

 him thus through the glass I see him pulling about the 

 piece of fish with the four pairs of small pincers of the first 

 two pairs of legs. In front of the legs I now see a strong 

 pair of foot-jaws which work from side to side towards the 

 middle line and lie over the mouth. Between these, 

 which are strongly toothed, the food is crushed ; and be- 

 hind them I see other pairs of jaws working vigorously. 

 The piece of fish is thus being crushed and torn and 

 tucked into the mouth. And every now and then when 

 he has got well hold of a bit with his strong mandibles, 

 which lie just outside the mouth, he pushes the fish away 

 with his foot-jaws and tears off a morsel. You must notice 

 that these jaws and foot-jaws, which you can examine more 

 closely in the dead crayfish, all lie outside the mouth. 

 The crayfish seems to enjoy his food, but whether he has 

 organs of taste in or near the mouth is not certainly 

 known. 



You will probably not be able to keep the crayfish long 

 in captivity as a pet. A basin of water is a poor substitute 

 for the dancing rippling stream in which he was wont to 

 live a free and active life, with many dangers, indeed, but 



U 2 



