140 PROCEEDINGS OF THE ACADEMY OF 



In examining various common animals of our household, Prof. 

 Leidy had found a thread worm, infesting the common house-fly. 

 The worm is from a line to the tenth of an inch long, and lives in 

 the proboscis of the fly. It was found in numbers from one to 

 three in about one fly in five. The parasite was first discovered 

 in the house-fly of India, by the English naturalist, Mr. H. J. 

 Carter, who described it under the name of Filaria Muscx, and 

 suggested the opinion that it might be the source of the Guinea 

 worm, Filaria Medinensis in man. Mr. Carter states that he 

 found from two to twenty of the worms iu one fly of three. Dr. 

 Diesing referred the parasite to a new genus with the name of 

 Habronema Muscse. The singular position in which the worm 

 lives suggests the man}' unsuspected places we have to search to 

 find the parents or offspring of our own parasites. 



Notice of some Fresh Water Infusoria. Prof. Leidy remarked 

 that a species of Limnias, belonging to the order of wheel animal- 

 cules, or Rotatoria, was exceedingly abundant in our rivers. It 

 lives in a tube, of its own construction, attached to aquatic plants 

 and stones. He had not been able to determine whether it was a 

 diflerent species from the L. ceratophylli of Europe. The latter 

 Is described as solitary, but the common Limnias of our rivers is 

 remarkable for the dense bunches that it forms. In many locali- 

 ties of the Schuylkill almost every stone exhibits multitudes of 

 such bunches, pendent from the sides and under part. The 

 bunches are conical, and usually one tube serves as a pedicle, 

 while the others hang from it and often curve outwardly. From 

 two or three to as man}' as fifty tubes may be counted in a bunch. 

 This fasciculated character mav distinguish the animalcule as a 

 variety, which might l)e named L. socialis. 



The bunches of Limnias form a support for a multitude of 

 other animalcules. Among the latter, C'otJiurnia pusilla is quite 

 common. Prof. Leidy had also observed upon the bunches on 

 several occasions the curious branching infusorium described by 

 Ehrenberg, and also described and figured by Claparede under 

 the name of Dendrosoma radians. This measures a half a line 

 or more in length, and terminates in branchlets, each with a 

 rounded end, from which project a multitude of delicate raj'S, 

 extending as much as the one-twelfth of a line in length. 



September 1. 



The President, Dr. Ruschenberger, in the chair. 



Fifteen members present. 



Dr. Nolan, having announced the death of Dr. John Hamilton 

 Slack, made the following remarks : 



