IV ENEMIES OF THE OYSTER III 



when we meet with still another in the cuiled-up condition in 

 which they gorge themselves, and as we drag it shorewards the 

 shell of a Tapes pullastra drops from the relaxing grasp of the 

 ogre. Slowly the extended stomach returns to its place, and 

 the monster settles back to an uncomfortable after-dinner siesta 

 on an exposed boulder; for the starfish wraps its turned-out 

 stomach around the prey it has secured, in place of attempting 

 to devour the limey covering in which most of its game is 

 protected. Once the mouth of the shell is enclosed in the 

 stomach of the starfish, the creature soon sickens, the hinge- 

 spring relaxes its hold, and the shell opening permits the star- 

 fish to suck out the gelatinous contents, and cast free the 

 calcareous skeleton." ^ 



According to other observers the starfish seizes the oyster 

 with two of his fingers, while with the other three he files away 

 the edge of the flat or upper valve until the points of contact 

 with the round valve are reduced almost to nothing ; then he can 

 introduce an arm, and the rest is easy work. Others suggest 

 that the starfish suffocates the oyster by applying two of its 

 fingers so closely to the edge of the valves that the oyster is 

 unable to open them ; after a while the vital powers relax and 

 the shell gapes. The Rev. J. G. Wood holds ^ that the starfish 

 pours a secretion from its mouth which " paralyses the hinge 

 muscle and causes the shell to open." Sometimes in a single 

 night a whole bed of oysters will be totally destroyed by an 

 invasion of starfish. Another dreaded enemy is the ' whelk,' a 

 term which includes Purpura lapillus^ Murex erinaceus^ Buc- 

 einnm undatum., and probably also Nassa reticulata. All these 

 species perforate the shell with the end of their redula, and then 

 suck out the contents through the neatly drilled hole. Skate 

 fish are the cause of terrible destruction in the open beds, and a 

 scarcely less dangerous visitant is the octopus. Crabs crush the 

 young shells with their claws, and are said to gather in bands 

 and scratch sand or mud over the larger specimens, which makes 

 them open tlieir shells. Yet another, and perhaps unconscious, 

 foe is found in the common mussel, which takes up room meant 

 for the young oysters, grows over the larger individuals, and 

 harbours all sorts of refuse between and under its closely packed 



1 "W. Anderson Smith, Loch Creran, p. 228. 



2 Longmans^ Magazine, June 1889. 



