Preface v 



rules for the care and treatment of the aqua- 

 rium, refraining from recommending com- 

 plicated implements difficult to handle and 

 needing a good deal of care and attention 

 to do their work well, but substituting in 

 their place the simplest instruments, or, in 

 many cases, dispensing entirely with their 

 service. 



We beg to express our sincere thanks to 

 Mr. E. F. Keller and to Mr. E. R. Sanborn 

 for their kind and important assistance in 

 the production of this book. With rare 

 skill and inexhaustible patience they have 

 prepared most of our illustrations. Who- 

 ever has tried to photograph live aquatic 

 animals in their natural element, will appre- 

 ciate the difficulties to be overcome in ob- 

 taining such excellent results. 



Otto Eggeling. 

 Frederick Eiireneerg. 



