APPENDIX 243 



in the narrow sandy spaces between one madrepore and 

 another. 



Oysters are very common on the rocks. The pearl oyster, 

 Meleagrina margaritifera, lives in depths up to sixty feet and 

 more. The big tridacna with a green, purple, blue or red 

 mollusc of flowering flesh, is frequent everywhere. Around 

 this mollusc — and I am speaking of the species we met in the 

 Red Sea — legend has built up grisly stories of pearl fishers 

 whose hand or foot has been trapped and who have then 

 perished by drowning. Apart from the fact that it is not so 

 easy to get caught by the hand and still less by the foot in 

 the valves of these furbelowed clams (I am still considering 

 the moderate sized species of the Red Sea), these bi-valves 

 are not so firmly fixed as to resist an uprooting even to the 

 point of pulling away the piece of madrepore to which they 

 are attached. According to some sources, the pearl fishers of 

 other seas who are caught by the foot by the Tridacna gigae, 

 amputate their limb with an ordinary knife and then 

 reappear on the surface as lively as ever. These fishermen 

 must be supermen. Cutting off one's own leg can be no joke. 

 And how is it done in apnoea ? An optimistic estimate of the 

 time needed for an operation of this sort using an ordinary 

 knife cannot be less than 15-20 minutes, which is what it 

 would take in a properly equipped operating theatre where 

 the patient was not also the surgeon. How then could a bone 

 be cut or a foot detached in the maximum time of five 

 minutes, assuming that these demon fishermen could survive 

 for so long underwater ? 



