158 PROCEEDINGS OF THE ACADEMY OF [1887- 



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. 



Dr. Bowerbank's "Monograph of tlie Spongillidre," (Proc. ZooL 

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

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

 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 Avriters 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. 



A further purpose, and one that I hold much at heart, is the 

 desire to revive, among scientists and lovers of nature, an apprecia- 

 tion of the apparently almost forgotten fact of the existence of sponges 

 in our fresh water; to show them that they are easily found and 

 collected ; that they are deeply interesting as living subjects of study, 

 microscopic and otherwise ; and that, by simple processes, their typ- 

 ical parts may readily be prepared for classification and the 

 permanent preservation of their various singular forms. With this 

 end in view the situations and conditions in which the American 

 species were found, have been briefly described, suggesting the hope- 

 fulness of an exploration of similar localities in other neighborhoods. 



During the last six or seven years the leisure time of a very busy 

 life has been largely occupied in the collection and examination 

 of sponge material. In this labor of love I have been greatly aided 

 by the contributions and correspondence of friends, till then 

 unknown, in widely separated districts, for whose thoughtful kindness 



