382 



MANUAL OF THE MOLLUSCA. 



lavour with Portuguese sailors, as " live sea-stock ;" and they have natu- 

 ralized the commou garden-snail of Europe {Helir as2)ersa) in Algeria, the 

 Azores, and Brazil ; and Helix ladea at TenerifFe and Mte. Video. Achatina 

 ftdica has been taken from Africa to the Mauritius, and thence to Calcutta, 

 where it has been established by a living naturalist ; and Helix kortensis has 

 been carried from the old country to America, and naturalized on the coast 

 of New England and the banks of the St. Lawrence. Bulhims GoodaHi, 

 indigenous to the West Indies and_S. JjEnerica,,. has been introduced into 

 EnglisiVprneriesTnd to Mauritius.- Helix pidchella, one of the small species 

 found in moss and decayed leaves, inhabits Europe, the Caucasus, Madeira, 

 the Cape (introduced), and N. America as far as the Missouri. Helix cellaria 

 inhabits Europe and the Northern States of America, and has been carried 

 abroad with the roots of plants, or attached to water-casks, and naturalized 

 ^ at the Cape and New Zealand. 



The fresh-water Fulmonifera—Limnaa, FJiysa, Planorbis, Jncylus— 

 and the amphibious Succinea, have a nearly world-wide range; and like 

 aquatic plants and insects often re-appear, even at the antipodes, under 

 familiar forms. The range of the gill-breathing fresh-water shells is more 

 restricted. 



The Old World and America may be regarded as provinces of paramount 

 importance, having no species in common (except a few in the extreme 

 north), and each possessing many characteristic genera. 



The Land Provinces represented on the map are the principal Botanical 

 Regions of Prof. Schouw, as given in the Physical Atlas of Berghaus; and it 

 is proposed to inquire how far these divisions are coniirmed by the land and 

 fresh-water shells, more especially by the land-snails, {Helicida, Limacida;, 



