A MANUAL 



OF THE COMMON 



INVERTEBRATE ANIMALS 



EXCLUSIVE OF INSECTS 



By 

 HENRY SHERRING PRATT, PH.D. 



Professor of Biology in Haverford College and Instructor in Comparative 



Anatomy in the Marine Biological Laboratory at Cold 



Spring Harbor, Long Island 



WITH OVER ONE THOUSAND 

 ILLUSTRATIONS 



CHICAGO 



A. C. McCLURG & CO. 



1916 



