ADVANCE PAGES FROM 



ATERS 



An elementary text book of fresh-water biology 

 for American students 



By 



JAMES G. NEEDHAM 



Professor of Limnology in Cornell University 



and 



J. T. LLOYD 



Instructor in LiAnoIogy in Cornell University 



Issued for the temporary tise of the 

 . . class in General Limnology in 



\n Comeil University 



37 



and published by 



The Comstock Publishing 

 Company 



Ithaca, New York 



