18 NOTES ON THE NATURAL HISTORY OF THE BELL ROCK. 



themselves some wonderful mechanism. Placing a fly on 

 the extremity of one of the tentacles, it was immediately 

 held fast. The whole of the tentacles then curled inwards, 

 carrying the fly with them, thus clearly showing their 

 function. 



The heavy easterly surf has deprived us for the present 

 of our fishing, forcing the fish off the rock to deeper water. 

 There are evidently plenty about, as the gannets are to be 

 seen busy diving in the vicinity. It is extremely interesting 

 to watch these birds pursuing their prey. Flitting near the 

 surface, they enter the water at an angle of about twenty 

 degrees ; again, at a higher altitude, they drop like a plum- 

 met, describing an arc of bubbling foam from their entrance 

 to where they emerge with a bounce a few feet further ahead, 

 beating the water with their wings for several yards before 

 being again fairly on the wing. The air cells pervading 

 various parts of the body of a bird, and which contribute to 

 its buoyancy, are probably vested in a greater degree in the 

 gannet, an extremely large one being situated in front of the 

 forked bone, or clavicles. Several instances are recorded 

 where a bird which had its windpipe temporarily obstructed 

 was able, by means of these cells, to carry on the function of 

 respiration through the wing bone, the broken end of which 

 protruded through the skin. The voluntary compression of 

 these cells, by expelling the air, destroys the buoyancy of the 

 bird, and explains the amazing rapidity of its descent. An 

 objectionable method is practised in some places for the 

 capture of these birds. A submerged piece of planking with 

 a herring fixed to its upper surface is set adrift, or towed 

 from a boat, in the vicinity of their fishing grounds. Swoop- 

 ing from an altitude, say, of a hundred feet, they apparently 

 see but the herring alone, with the result that their necks 

 are dislocated by impact with the plank, the impetus of their 

 descent being sometimes so great as to bury their bills to the 

 base in the wood. It is a common sight here, during the 

 breeding season, to see these birds trooping past in Indian 

 file to their home on the Bass Rock, in batches of a dozen 



