BOOK OF NATURE LAID OPEN. 129 



penetrating rays of the sun, and so firmly cemented 

 to the rock by means of the broad muscular surface 

 he presents, that neither storm nortempest can prevail 

 to loosen his grasp, or make him relinquish his firm 

 hold. The Muscle is not provided by nature with 

 such a strong and firm sheet-anchor, but she is taught 

 to supply the defect by a rt, and to spin to herself 

 cables, by which she can be moored in security to 

 her favourite spot. The Periwinkle does not at- 

 tach itself so firmly as either of these, nor has she 

 the means or the power to do so ; but her stony ha- 

 bitation is almost proof against accident, and she can 

 roll about in safety, hermetically sealed up tfnder 

 her scaly covering The Cockle burrows deep in 

 the sand or mud, and its edges are notched, in order 

 to enable it to clasp more firmly together. The 

 Nautilus, which can exist either as a diver or swim- 

 mer, and lives sometimes at the bottom, and some- 

 times on the surface of the ocean, has a power of 

 contracting and drawing itself into its shell when it 

 has occasion to descend to the bottom, and of un- 

 folding and expanding its oars and sails, when it 

 has an inclination to sport on the surface. The 

 Cutler, or Razor fish, never creeps, but penetrates 

 perpendicularly into the sand; and how nicely is 

 its long and slender shell formed for this purpose ! 

 The Crab is provided with, claws and -feet for 

 scrambling about, but amongst such rugged preci- 

 pices, and with so many enemies to encounter, it 

 must often be at the expence of a limb; and, lo ! it 

 is endowed with the singular property of shaking off 



