CONTENTS. 



(In this reprint the paging of the Proceedings of the Academy of Natural Sciences 

 of Philadelphia has been retained for convenient reference.) 



Preface: — Scope and purpose of the work: acknowledgements. 158 



Introduction: — Elementary information as to Sponges; 160 

 External appearance; ^ 162 



Favorite situations; modes of search ; 163 



Special subjects for study ; 1 64 

 Propagation for minute examination of living 



sponges; 165 



Collecting and preserving; 167 



Determination of species ; 168 



Variability of species. 170 



Characteristic features of some localities mentioned. 



A New Jersey Cedar Swamp. 185 



Fairmount Dam, Philadelphia. 213 



Brand V wine Creek, Pennsylvania. 229 



Ut. Everett, Massachusetts. 231 



The Colorado of the West, Mexico. 235 



Lehigh Gap, Pennsylvania. 238 



River Amazon, South America. 254 



Chester Creek, Pennsylvania. 264 



Lansdowne Run, Philadelphia. 266 



Key to the genera of Fresh water Sponges. 181 



Key to the sj^ecies (17) of the genus Spongilla. 183 



Key to the species (17) of the genus Meyenia. ' 210 



Key to the species (4) of the genus Heteromeyenia. 237 



Key to the species (5) of the genus Tubella. 248 



Key to the species (3) of the genus Parmula. 256 



Key to the species (4) of the genus Carterius. 261 



Total, 50 species in the Group Spongillina; 8 species in the 

 Provisional Group. 



(I) 



