VIII PREFACE. 



with those of warmer climates ; yet the lime- 

 stone of Devon and the slate rocks of Cornwall 

 contain the remains of specimens, which for 

 size and beauty might have vied with any now 

 existing. Though the Cornish species are small, 

 yet many of them are exceedingly elegant, and 

 seem peculiarly fitted to invite attention. To 

 myself the investigation it has been rather the 

 amusement of leisure hours and pleasurable 

 excursions on the water, than a study ; had it 

 however, been otherwise the pleasure derived 

 from it would more than have compensated for 

 any difficulties that could have occurred. It 

 has been a source of health, innocent amuse- 

 ment and pleasure, and will be so to all who 

 study nature where she is to be found ; abroad 

 rather than in the closet. As Cornwall, from 

 its form has a very great extent of sea coast, 

 some species have probably escaped detection ; 

 but as it is to be hoped that the number of 

 observers will now be increased, these will 

 soon be found, and where there is any doubt 

 or difficulty, I shall esteem it a favour to be 

 allowed to inspect such specimens, as w r ell for 

 my own, as for the benefit of others. 



Penzance, August, 184-t. 



