30 



PHOLAS. 



into the air when alarmed by its hunter's foot- 

 step. Into the hole from which the jet ascended 

 the fisherman plunges a slender iron rod, which 

 having a barbed, harpoon-like head, pierces the 

 animal, and retains it while it is dragged from 

 its hole. If, however, the fisherman takes a 

 bad aim, and misses his cast, he does not try 

 a second with the same creature, knowing that 

 it will have retreated to the termination of its 

 burrow, whence it cannot be extracted. 



Yet another burrowing shell. In most chalky 

 rocks, such as those of which the white cliffs of 

 old England are composed, many portions run 

 well out to sea. If these are examined at low 

 water they will be found to be perforated with 

 numerous holes, running to some depth, and 

 varying considerably in dimensions. These holes 

 are made by the Pholas dactylus, plate b, 

 fig. 9, one of the most remarkable animals ic 

 creaturedom. 



Hard rocks and timber are constantly found 

 perforated by this curious shell, but how the 

 operation is performed no one knows. It is the 

 more wonderful, because the shell is by no means 

 hard, and cannot act as a file. Indeed, in some 

 species, the external shell is almost smooth. And, 

 moreover, if the shell were used as the boring- 



