28 PROCEEDINGS OF THE ACADEMY OP [1884. 



February 5. 



The President, Dr. Leidy, in the chair. 



Twenty-seven persons present. 



The following papers were presented for publication : — 



" Notes on a Collection of Anchovies from Havana and Key 

 West, with an account of a new species, Stolephorus eurystole, 

 from Wood's Holl, Mass.," by Jos. Swain and Seth E. Meek. 



" On a new species of Rotifer, of the Genus Apsilus," by 

 Sara Gwendolen Foulke. 



The death of Wm. T. Haines, a member, was announced. 



February 12. 



Rev. H. C. McCooK, D. D., in the chair. 



Thirty persons present. 



A paper entitled " List of Fishes from Egmont Key, Florida, 

 in the museum of Yale College, with descriptions of two new 

 species," by David S. Jordan, was presented for publication. 



Fresh-water Sponges as improbable causes of the pollution of 

 river-water. — Mr. Potts reported that on the 9th of February 

 he had visited and partiallj'^ examined the forebay at Fairmount 

 Water-works, on the Schuylkill River, from which the water had 

 been temporarily withdrawn, with a view to discover the winter 

 condition of the fresh-water sponges and the other inhabitants 

 of that locality. He found far the larger part of the wall surface 

 below the water-line inaccessible on account of a thick deposit 

 of mud upon the bottom, and much water remaining in the fore- 

 bay. Wherever reached, however, and so far as the eye could 

 detect in other places, it was covered by a mud-colored incrusta- 

 tion of considerable thickness, which a more minute examination 

 showed to be composed almost wholly of the statoblasts and 

 spicules of tlie sponge Meyenia Leidyi. Some few fragments 

 of Meyenia fluviatilis and Spongiila fragilis were seen, but the 

 first-named was clearly the prevailing species. 



A sluiceway which formerly supplied the last of the old " breast 

 wheels " used in pumping into the reservoir, but from which the 

 water had been for many months excluded, was entered and 

 examined. Here the remaining incrustation (much having doubt- 

 less crumbled and fallen away) was from one-fourth to one-half 



