At the suggestion of the Director the sul (joined alphabetical indices have been 

 prepared to show students in which volume they may find memoirs in which they 

 are particularly interested. Owing to the fact that the memoirs were submitted to 

 the Editor at very various times, and as it was important to publish them as soon 

 as possible after their reception, the fifty memoirs in the five volumes of " Zoology 

 and Botany " necessarily deal with subjects not closely allied in any systematic 

 arrangement. 



F. J. B. 



February 16th, 1912. 



