INTRODUCTION. V 



habits, and customs must be of great importance in countries 

 infested with them, so as to be able to provide a remedy 

 against them. Snails and slugs are also enemies much to 

 be dreaded in our gardens. 



Lamarck, in his last work, the result of the successive 

 and continual labours of his whole life and those of his con- 

 temporaries, has rendered a very great service to science, 

 but especially to conchology, by describing, or, at least, char- 

 acterizing the numerous species of shells in his own splen- 

 did cabinet. It may be proper here to remark, that a part 

 of Lamarck's cabinet is now in the possession of Isaac Lea, 

 Esq., of Philadelphia, to whom we are much indebted for 

 valuable assistance. To Dr. Comstock, and the Rev. W. 

 Turner, of Hartford, Conn., we are much indebted for kind 

 favours ; their aid has greatly facilitated our labours. 



In this Manual of Conchology we have endeavoured to 

 give a free translation of Lamarck's system, as simplified 

 by De Blainville ; and, in order to facilitate as much as pos- 

 sible the study of this beautiful and interesting science, we 

 have divested it of numerous technicalities, and divided it 

 into four classes : Annelides, Cirrhipedes, Conchifera, and 

 Mollusca. 



To each class we have assigned its various families, to 

 each family its genera, and to each genus its living species ; 

 thereby making it plain and within the reach of the meanest 

 capacity. A type of almost every genus is given, excepting 

 only those shells which, from their similarity to other genera, 

 may easily be classed. 



It was deemed advisable, as this is intended for an easy 

 introduction to the science, to omit many divisions and sub- 



