PLATES. 



Note. 



The figures of the plates could not be numbered without great inconvenience 

 to the printer, on which account I have adopted a rule applying to all, which 

 I think will serve the purpose. 



In all the text references the upper right-hand figure is i ; the upper left-hand 

 figure is 2 ; the lower left-hand figure is 3, and the lower right-hand, 4. Some 

 plates have several figures on each of their two or four principal divisions. In 

 these cases, to save the reader from mistakes and confusion, I have been very ex- 

 plicit in my descriptions, in indicating the particular figure referred to. 



