248 



hole. It seems> then, that lie is aware of the snare Hint' 

 is laid for him, and is unwilling to be taken by it. 



16. Cast your eyes on this stone, which I have just 

 wow taken up from the sea-shore. A shell-fish fixes 1m 

 habitation in it. Observe, that on the surface of the- 

 stone there is a very little hole ; it is by that the shell- 

 fish has entered, and you may judge of the sniallness of 

 it by that of the aperture. We will break the stone 

 asunder, that we may see the animal that dwells in it. 

 How great must your suprise be ! You behold a great 

 shell-fish, near three feet in length, whose shell is formed 

 of three smooth pieces, joined together by a ligamentary 

 membrane. It is lodged in a great cavity, that is hollow 

 Ijke a funnel : the upper part of the cone is in the little 

 hole you see on the surface of the stone. This shell* 

 fish is a daily or pholas. How could it be able to pierce 

 so hard a stone? Or how go through so narrow a pas- 

 sage? Draw near this clayey shell which the wave has 

 just left. It is pierced through with a multitude of 

 such holes as you see in the stone you have in your 

 hand. All these holes are inhabited by young dails^ 

 which are only a few lines long: they had then no oc- 

 casion to penetrate into a hard stone. Moist clay makes 

 but little resistance. But the sea insensibly converted : 

 this clay into stone : the dail, which at first found him- 

 self lodged in a soft earth, afterwards perceived that lie 

 was within a stone cell. We have seen that the cutler 

 can come out of his hole when he pleases : the dail 

 never quits his; nor indeed can he ; since the form of 

 this kind of cell will not admit of it. All that lie can 

 do is, to stretch out two pipes at the opening of the 

 hole, with which he receives and rejects the water: the 

 cutler does the same. You are impatient to be inform- 

 ed of the instrument with which the dail hollows his 

 cell : this instrument has no edge, to it; it is purely, 

 fleshy, arid shaped like a lozenge. 



1.7. We will quit shell-fish for a time. Divers am- 

 puls of the sea will likewise entertain us with the \voji- 



3- 



