To THE MEMORY OK 



DOCTOR ISAAC LEA, 



WHO, GIVING THE BEST YEARS OF HIS LIFE TO THE STUDY OF THE 

 NAIADES, CLEARLY RECORDED AND SUMPTUOUSLY ILLUSTRATED 

 HIS RESEARCHES UPON THEM, AND GAVE TO THE UNITED 

 STATES NATIONAL MUSEUM THE UNRIVALED COL- 

 LECTION THE STUDY OF WHICH HAS MADE 

 POSSIBLE THE PREPARATION OF THE 

 PRESENT WORK; AND TO 



MRS. FRANCES LEA CHAMBERLAIN 

 AND THE 



REVEREND DOCTOR LEANDER T. CHAMBERLAIN, 



THROUGH WHOSE GENEROSITY THE PREEMINENCE OF THE COLLEC- 

 TION HAS BEEN MAINTAINED AND THE LITERATURE 

 GATHERED FOR MONOGRAPHIC STUDY, 



THIS WORK IS RESPECTFULLY DEDICATED. 



