Of the Habitation of Shells. 



Shells maybe divided, Avith reference to the 

 places they inhabit, into terrestrial, river, and ma- 

 rine, that is, into those living on land, in fresh 

 water, or in the sea. It is the opinion of Bruguiere, 

 that we know less of land than of sea shells. He 

 affirms, that the shells of the Mediterranean sea are 

 nearly the same, from the Straits of Gibraltar to 

 the island of Sicily ; while the land shells of Lan- 

 guedoc often differ from those of Provence, of 

 Dauphiny, of Piedmont, and of different parts of 

 Italy. We find shells in Spain, in Corsica, in 

 Sardinia, and in Sicily, which are not to be met 

 with elsewhere ; and if (adds Bruguiere) we may 

 found our opinion on what has been sent from those 

 countries, we may rest assured that the sea produces 

 scarcely any thing new, while the unknown land 

 shells are still very numerous. This may possibly 

 be the case with respect to the Mediterranean ; but 

 it will not apply to many other parts of the world, 

 as we are daily getting fresh accessions of new ma- 

 rine species, and, where they are not discovered, it 

 is more for want of diligence in the search, than 

 variety in Nature. 



