CHAPTER XIV. 

 SEA-SNAILS AND SEA-SLUGS. 



MOLLUSKS that have their shell all in one piece are technic- 

 ally known as the Gasteropoda, or belly-footed creatures ; but 

 for our purpose the term sea-snail will serve admirably, for it 

 is a popular term that will not cause misunderstandings, as 

 many popular general terms do. The sea-snails, as living 

 creatures, are more amenable to study by the shore-naturalist, 

 than is the case with the bivalves ; and every rock, whether it 

 be thickly clothed with weeds, or bare and exposed to the full 

 fury of the waves, will provide us with specimens. It is true, 

 that all visitors to the sea-shore are well acquainted with the 

 most plentiful of these the periwinkle, the purple, and the 

 limpet. But though they are familiar with the forms and 

 names of such common objects, there may be among my 

 readers some to whom the principal facts in the economy and 

 structure of these species may be new or interesting. 



I fear, that in popular estimation, there is but one kind of 

 Limpet. As a matter of greater exactitude, I may say that 

 eight or nine species may be found on our shores ; and we may 

 find some points of interest even in the too common species 

 (Patella vulgatci). Only those perhaps who have been badly 

 in want of bait for a little fishing have troubled to see what is 

 beneath the conical shell ; but the shell itself is worthy of a 

 little attention. What could be better adapted for the animal's 

 mode of life than this ? The Limpet is not a deep-water mol- 

 lusk, but lives between tide-marks, where it receives the full 

 force of the waves as they beat and hammer the rocks in 



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