In the Little Brook 289 



scendants would never quite forget it. Some little trace 

 would be kept by the clinging force of heredity, and at some 

 time or another this rudiment would appear. And the lower 

 jaw too, for that is really another pair of limbs joined to- 

 gether in front — as it were, a pair of short hands clasped 

 together and never unlocked. 



But though the lampreys have no limbs and no jaws and 

 are not real fishes anyhow, they do not know the difference, 

 and come up the brook in the spring, rushing up the rapids, 

 swirling about in the eddies, just as if they were real fishes 

 and owned the brook themselves. They are long, slender 

 and slippery, shaped like eels, without any scales and with 

 only a little fin, and that along the back and tail, an out- 

 growth from the vertebral column. 



The vertebral column itself is limp and soft, the vertebrae 

 only imperfectly formed and made of soft cartilage. In 

 front the lamprey seems to be cut off short, but if we look 

 carefully we see that the body ends in a round disk of a 

 mouth, and that this disk is beset by rows of sharp teeth. 

 A row of the sharpest of these is placed on the tongue, and 

 two of these are above the gullet, for the tongue to scrape 

 against them. And the rest are all blunt and are scattered 

 over the surface of the mouth, which has no lips or jaws, 

 but is surrounded by a belt of fringes. 



When the lamprey is hungry he puts his mouth against 

 the side of some fish, exhausts the water between, and then 

 the pressure of the outside water holds him there tightly. 

 When this is done, the fish swims away and the lamprey 

 rides with it, giving no thought to where he is going, but 

 all the while scraping away the flesh with his rasp-like teeth. 

 When he has filed ofif enough fish flesh and sucked enough 

 fish blood to satisfy his hunger he lets go, and goes off 

 about his business. The fish, who does not know what 

 hurt him, goes off to get well if he can. Usually he can not, 

 for the water of the brook is full of the germs of little 

 toadstool-like plants, and these fasten themselves on the 



