6o STRANGE DWELLINGS, 



species, the Fork-tailed Date Shell {Lithodomus caudigerd), is able 

 to bore into substances which the pholas cannot penetrate. It is 

 truly a wonderful little shell. Some of the hardest stones and 

 stoutest shells are found pierced by hundreds of these curious 

 beings, which seem to have one prevailing instinct, namely, to 

 bore their way through everything. Onwards, ever onwards, 

 seems to be the law of their existence, and most thoroughly do 

 they carry it out. They care little for obstacles, and if one of 

 their own kind happens to cross their path, they quietly proceed 

 with their work, and drive their tunnel completely through the 

 body of their companion. 



The precise method employed in excavation is at present un- 

 known, for the shape of the shell, and the exactitude with which 

 it fits the burrow, prove that the mollusc does not form its tunnel 

 by means of the protuberances on the surface of the shell, and 

 no other method of boring has at present been discovered. 



Those who are fond of wandering on the sea-shore, will often 

 have experienced tangible proofs of the existence of another 

 burrowing mollusc, the Razor Shell {Solm ensis). 



In some parts of our coast it is impossible to walk on the 

 mixed rock and sand, when the tide has receded, without no- 

 ticing innumerable jets of water, which start from the ground 

 without any perceptible cause, leap for a foot or so in the air and 

 then disappear. On watching one of these miniature fountains, 

 and looking at the exact spot whence it proceeds, two little 

 round holes are generally seen in the sand, so close to each 

 other as to resemble a keyhole, and large enough to receive an 

 ordinary goosequill. If the finger be placed on the spot, or even 

 if the foot descends heavily on the ground, the curious object 

 vanishes far out of the reach of a probing finger. The jets are 

 thrown up by the Solen, and the two little holes are the open 

 extremities of the siphon, that wonderful instrument through 

 which the creature obtains its nourishment. 



The reader will remember that the wood-bearing pholas 

 always makes its burrow across the grain of the timber which it 



