PERIWINKLES WHELKS. 31 



Mussel, and observed the result. In a short time the 

 Purpura, finding the Mussel was not at all open to 

 his advances, and that the valves of the shell were so 

 firmly drawn together as to leave no chance of effect- 

 ing an entry between their edges, began to think of 

 attacking them from without. Seeking a portion of 

 the outer surface free from epidermis, he commenced 

 boring. His human observer repudiating the policy 

 of ' non-interference,' removed him, and turned the 

 Mussel over, placing that valve uppermost which 

 was most covered with the horny protection; the 

 creature soon managed to turn over the huge body 

 and shell of the Mussel, and resumed his operations 

 at the point where he left off when disturbed; and he 

 did this repeatedly after similar interruptions. At 

 last, quite satisfied that the breach would in time be 

 effected in that way, Mr Bates resolved to wait no 

 longer for the process, but at once give the voracious 

 shell-fish an opportunity of satisfying his appetite, at 

 a smaller demand of exertion from itself and of 

 patience from its observer. To this end he cut the 

 muscles of the Bivalve, so as to deprive it of the 

 power of keeping its valves closed. Its fate was thus 

 accelerated; it was now at the mercy of its enemy. 

 The latter no sooner perceived the valves open, than, 

 leaving his former work of boring, he seized his ad- 

 vantage by inserting his trunk between the valves, 

 not in this instance acting upon the general rule, that 

 the enjoyment of an acquisition is increased in pro- 

 portion to the difficulty and trouble of obtaining it." 



