PREFACE. 



My attention was especially directed to the subject of tlie distribution 

 of the land shells of the West Indies in 1849, by Professor C. B. Adams, 

 with whom I then, in the island of Jamaica, had first the pleasure of 

 becoming acquainted. In conjunction with the Hon. Edward Chitty, I 

 aided him in his researches in that island. During the same year, after 

 his return to the United States, Professor Adams commenced the pub- 

 lication of his " Contributions to Conchology." I continued in corres- 

 pondence with him until the middle of 1852, in the Autumn of which 

 year I resided for several months at Amherst; he was then engaged in 

 issuing his admirable work on the Shells of Panama. 



Zoological Geography at this time very much engrossed the attention 

 of Prof. Adams, as well as my own ; and our discussions on the subject 

 resulted in the publication by him, in No. 11 of the "Contributions," 

 (Oct., 1852) of a paper entitled "Hints on the Geographical Distribu- 

 tion of Animals, with especial reference to the Mollusca," and by 

 myself, in the American Journal of Science and Art (Nov. 1852) of 

 one bearing the title of "Facts and Principles relating to the Origin 

 and the Geographical Distribution of Mollusca." 



In order to improve his impaired health, and earnestly wishing to 

 complete the collection of facts, with a view to an elaborate work on 

 the Caribbean Zoological Province, Professor Adams determined upon 

 a visit to the West Indies. He left New York for the Island of St. 

 Thomas early in December, 1852, arrived there on the lYth, and took 

 up his abode, as he had been kindly invited to do, with our mutual 

 friend, Mr. Robert Swift. On the 18th of the same month the Professor 

 wrote to me, describing the great number of individuals of marine and 

 terrestrial species of shells which he had collected during a stay at 

 Bermuda, on his passage to St. Thomas, of less than forty-eight hours. 

 As an illustration of his activity and enthusiasm, I extract the following 

 passage from the letter referred to, the last which I received from him : 

 — " I was perfectly enraptured with Bermuda for scenery and shells. 

 I must have taken three or four thousand specimens, not yet assorted. 



