BULIMUS. 189 



boklt ; tlieir calcified condition corresponding also witli the 

 northward curves in his isothermal lines along the western 

 coasts of South America, and those bending southward on 

 the eastern side. Consequently such Bulind as inhabit 

 Chili are less vivid in their tints^ 0T\fing to the vapours 

 precipitated by the great Atlantic current of cold water, 

 which flows nearly to the Gallapagos Islands, than such as 

 are assigned to the opposite Brazilian coast, beside which 

 the equinoctial current rushes with its mighty waters. 

 Eecent geological changes which have taken place in the now 

 barren and riverless Patagonia, have suddenly arrested the 

 genus; and with reference to the distant islands of the 

 Pacific, Bulimi ai'e curiously represented by other genera 

 of terrestrial moUusks; while species inhabiting islands 

 that approximate towards the neighbouring continents, as 

 Trinidad for instance, partake of characteristics that pertain 

 to those of the main land. 



The European species belong to the Caucasian type, 

 which has its centre in Asia Minor. Shells of its numerous 

 genera are mostly colourless, owing to the dry and juiceless 

 character of the thorny vegetation, which affords but scanty 

 nutriment ; and the mollusks them'selves, having little 

 inducement to roam abroad, mostly remain concealed under 



