MARINE ANIMALS THAT BITE 



31 



TRIDACNA CLAMS 



The so-called giant, or killer clams, (Fig. 10, Top) abound in 

 tropical waters. Some of them attain huge proportions, weighing 

 several hundred pounds (Fig. 11). Although accidents from them 

 are rare, one should learn to recognize them and to avoid catching 

 a foot or hand between the two valves. Drownings have occurred 

 from divers accidentally stepping into the open valves and becom- 

 ing trapped. Several such accidents are said to have taken place 

 along the Great Barrier reef of Australia. In order to release the 

 victim, a knife must be inserted between the valves and the ad- 

 ductor muscles must be severed (Fig. 10, Bottom). 



Fig. 11. Photograph of a large specimen of the giant tridacna clam in a tidal 

 pool along the Great Barrier Reef of Australia. (From Yonge) 



