History of Conchology in the United Stales. 17 



Isaac Lea, President of the Academy of Natural Sciences, 

 contributed his first paper on Conchology to the Philadelphia 

 Philosophical Transactions, vol. iii, 1828 ; and from that date 

 to the present time, a period of thirty-four years, he has given 

 unceasing attention to the science, and particularly to his chosen 

 speciality, the Naiades, with whose history he has become per- 

 fectly identified, having described five-sixths of all the recent 

 species published. 



There are but few authors who have so patiently, indefatigably 

 and successfully, worked up the subject of their studies as Mr. 

 Lea. He has contributed two hundred papers to the Proceedings 

 of the Academy, and of the Philosophical Society, describing 

 about 550 species of Naiades, 400 species of Melanians and other 

 fresh water shells, and 50 species of Terrestrial shells. 



These papers are elaborated in the Transactions of the Philo- 

 sophical Society, and Journal of the Academy of Natural Sci- 

 ences, 2d series, and are illustrated by excellent figures, many of 

 them colored. 



They have also been issued in eight quarto volumes, containing 

 in all 850 pp. and 198 plates, as follows : 



Vol. 



Mr. Lea has also published three editions of his "Synopsis of 

 the Family of Naiades," a work containing a list of the species 

 and their synonymy ; the shells being grouped according to ob- 

 vious external characters, in order to facilitate their determina- 

 tion. There is also a table of geographical distribution, and a 

 very full index and bibliography of the subject; making the 

 book an indispensable aid to those studying this interesting fam- 

 ily of shells. 



The third edition of the Synopsis was issued in 1852. (4to, 

 pp. 88.) Since that time many new species of Naiades have 

 been described, rendering a new edition necessary ; and on this 

 useful work, Mr. Lea is now engaged. 



He has also attentively studied the Melanians of America, 

 besides describing many exotic species for the Zoological Pro- 

 ceedings, London, 1850. 



His last paper in the Proceedings of the Academy contains 

 diagnoses of forty-nine new species of these shells, from Ala- 

 bama. Mr. Lea is still actively engaged in his favorite pursuits, 



