Xii INTRODUCTION. 



next in succession to that species it most nearly resem- 

 bles and approximates. 



The first column of the Catalogue which follows the 

 description of the genus will, it is presumed, be found 

 to contain a comprehensive list of all the species at 

 present described. In the second column is placed a 

 list of the localities, which from our connections we 

 have been able greatly to enrich and correct. The 

 last column contains the trivial or common names. 



The plates which embellish this work are taken from 

 specimens in our own cabinet, and we are indebted to 

 the kindness and indefatigable exertions of an artist 

 of the greatest talent, for the accurate and elegant de- 

 lineation of them. 



