INTRODUCTION. 



now k.unvn to exist in the fresh waters of that State alone, and .vhich have been described, 

 f „ my last volume the number mentioned was 120. In this volume it will be observed that 31 new 

 one. are added, thus making the number described from Georgia 151 species ! 



To these we may anticipate the addition of many more, as some are still in my possession unde- 

 .oribed, and there are very many portions of the State the streams of which no naturalist has as 



vet searched. 



■ The number of exotic .species described in^his volume is tbirty-nme ; some of them are very 

 peculiar, exhibiting new types, and all of great interest. They are carefully descnbed and well 

 illustrated, and will, I hope, advance a knowledge of this branch of the subject. The number 

 of indigenous species in this volume is also thirty-nine. 



The description and figures of the soft parts of some of the species not before represented, cannot 

 fail to interest the student of Malacology. By the kind assistance of many friends, I am m pos- 

 session of some 200 species in alcohol, which have all been most carefully exammed, and descrip- 

 tions made. What remains unpublished of these will follow in order, and the observations of the 



embryology, as occasion may occur, will also take their proper place in the next and succeeding 



volumes. 



