NOTE. 



In the present issue many small corrections, typographical and other, 

 have been made throughout the volume, as well as more considerable 

 alterations on pages 479, 480, 564 ; an omission of the proper acknowl- 

 edgment for the article on Sparganium is supplied on page 481 ; and 

 additional species, with a few more extended emendations, are given on 

 pages 679-682. 



Cambridge, January 30, 1868. 



