180 THE RING OF NATURE 



more sizes, and are hooked like the claws of the 

 cat or the thorns of a bramble. 



Where is that ' radula of Patella vulgaris ? ' 

 Behold the common limpet. That is Patella 

 vulgaris. If you are callous enough to wrench 

 one of these from its rock and, following the lead 

 of the little red mouth, probe it a little with a 

 needle, you can extract the radula like a reddish 

 thread nearly two inches long, and, nicely coiled 

 under the microscope, it will give you again that 

 astonishing picture of super-barbed wire. If we 

 draw the tiny thread through our fingers we can 

 feel the rasp of the tiny teeth, and understand a 

 little how the whole snail tribe files up green leaf 

 and tough bark for its food. There is a distinctly 

 different pattern of dentition for every family of 

 gasteropod, and a slightly different one for every 

 species. 



We should need many months of days far 

 more strenuous than a hot day in August to catch 

 and examine all the stomach- walking molluscs. 

 There are the tops, of a new and most beautiful 

 style of twist and exquisite colouring, of which we 

 shall find some in the lower pools, the pelican- 

 foot and its allies in gravel, the smooth and daintily 

 painted Natica burrowing in sand, the little English 

 cowrie, the body of which envelops the whole shell 

 when the animal is out, yet entirely withdraws 

 through a narrow crack when it is in, the staircase, 

 the turrets, and many more. 



Not of course the barnacles. They never come 



