Mo/lusca of British Guiana, 



By the Editor. 



[HE present communication deals with but the 

 land and freshwater forms of this group, 

 since up to the present, no detailed examina- 

 tion has been made of the marine species. As a group 

 of beings, the Mollusca or shell-fish, as the more common 

 forms are generally termed, are entitled to a considerable 

 degree of attention from a pra6lical stand-point. In 

 nearly all the tropical portions of the globe, various 

 forms, chiefly of the marine shell-secreting species, have 

 become the bases of by no means unimportant indus- 

 tries ; while in temperate as well as tropical climes, a 

 very considerable number furnish food, not only highly 

 nutritious but in a few cases, as in the Oyster, almost 

 unsurpassed for its delicacy. 



For a long time a small species of Cowry has 

 been utilised, in portions of W. Africa, as the medium 

 of exchange, and was imported in large quantities from 

 the Eastern seas; the great Fountain-shells or Strombs, 

 the Helmet-shells, and the large Cowries are choice 

 subje6ts for the costly cameos, and for this purpose are 

 largely imported into Europe ; the fine thread-like and 

 silky attachments of the great Wing-shells have been 

 utilised for the manufafture of various fancy articles ; the 

 Pearl and Mother-of-pearl shells form the staple of 

 extensive trades for the manufa6ture of jewelry and 

 other ornamental or useful articles ; while an enormous 

 number of other species are normal articles of house 



