CONTRIBUTIONS TOWARDS A SYNOPSIS OF THE AMERICAN FORMS 



OF FRESH WATER SPONGES WITH DESCRIPTIONS OF THOSE 



NAMED BY OTHER AUTHORS AND FROM ALL PARTS 



OF THE WORLD. 



BY EDWARD POTTS. 



PREFACE. 



Dr. Bowerbank's "Monograph of the Spongillidse," (Proc. Zool. 

 Soc, London, 1863 p. 440 etc.) and "The History and Classification 

 of the known species of Spongilla," by H, J. Carter Esq. F. R. S. 

 etc. (Annals and Mag. of Nat. Hist., London, 1881, p. 77 etc.) 

 contain the only complete synopses of the fresh water sponges, as 

 known at their respective dates. Both writers have, in their 

 introductory remarks, given full information as to the history and 

 bibliography of this branch of study, which it cannot be necessary 

 now to repeat. 



My design in the preparation of the present paper has been, 

 primarily, to describe those genera and species, mostly North 

 American, that have been discovered since the date of Mr. Carter's 

 publication; next, to detail the results of a somewhat extended 

 examination into the character and variations, in North America, 

 of those species that have long been familiarly known in Europe ; 

 and thirdly, to make it valuable for reference as a Monograph, by 

 adding brief technical descriptions of all other "good" species. 



