PREFACE TO THE PRESENT EDITION. 



The fifteen years that have elapsed since this work 

 was written have been prolific of discoveries in 

 Natural Science ; and, perhaps, in no dej)artment 

 has knowledge advanced so rapidly as in that of 

 Marine Natural History. 



The invention of the Marine Aquarium has not 

 only made the history of the wondrous creatures 

 of the Sea popular ; it has rendered the study of 

 them practicable to thousands, who, but for its 

 aid, v/ould have been entirely precluded from 

 acquaintance with them. 



The Autlior has subjected his work to a thorough 

 revision for the present edition ; cancelling some 

 papers which conveyed erroneous or defective im- 

 pressions, and re-writing and adding others, as the 



existing state of science demanded. 



Torquay, 



Oct. 1860. 



P. H. G 



