110 Beautiful Shells. 



are mysteries. The most common of them, perhaps, 

 is the Prickly Pidduck, or Peckstone (P. dactylus), 

 which is much used by the fishermen of our coasts 

 as bait ; the specific name is the Latin for a fruit 

 shaped like a finger, which is something like the 

 shape of this mollusk, as will be seen by the 

 annexed engraving. 



The genus Pholus is very widely distributed, 

 and all the species have the same boring habits as 

 those of our own coast, which we need not enume- 

 rate. Like them, too, in this respect, are the 

 marine worms called Teredo, which make their way 

 into the bottoms of ships, and all submerged timber, 

 but these will be more fully spoken of in another 

 volume. The above figure exhibits the Pholas dac- 

 tylus as it appears in a section of rock, split open 

 for the purpose of seeing the shelly miner at his 

 work. 



