1887.] natural sciences of philadelphia. 157 



May 31. 



The President, Dr. Joseph Leidy, in the chair. 



Twelve persons present. 



Asplanckna Ebheshorn'd. Dr. Leidy remarked that a few days 

 ago Mr. Wm. P. Seal, had submitted to him a four ounce bottle 

 swarming with animalcules, which at first glance he supjjosed to be 

 a species of Cypris, but on closer inspection he observed to be a rotifer. 

 As seen with the naked eye they appeared transparent whitish, and 

 of conical shape and about half a line in length. They swam ac- 

 tively, with the crown uppermost, and at all levels of the water. 

 The rotifer accords closely with the description of Asplanchim 

 Ebbesbornii, given by Hudson in the Journal of the Royal Micro- 

 scopical Society in 1883, p. 621, pi. ix, x. As in this it has a dor- 

 sal and ventral projection. At times it was observed that the rotifer 

 would retract the crown and project a pair of lateral conical horns, 

 when it would appear as broad as it was long. The stomach is yel- 

 lowish and suspended from the pharynx by a long narrow oesopha- 

 gus. There was a single eye. The animal is viviparous, and was 

 observed in a number of instances to suddenly give birth to a young 

 one which was about two thirds the size of the parent, and resem- 

 bled it in form. Specimens measured from J to 1 2 mm in length. 

 Mr. Hudson's specimens Avere obtained from a duck-pond in Wilt- 

 shire, England, the only known locality. Mr. Seal's specimens were 

 obtained from a "filthy sewage-fed pond, a duck-pond and hog-wal- 

 low" below the city. In summer it is com])letely covered with duck 

 weed, Lemna. The water swarms with the rotifer in company with 

 Daphnia. Mr. Seal remarks that he noticed sand pipers about the 

 place and thinks these birds are especially instrumental in distrib- 

 uting the lower forms of aquatic life. 



The following were elected correspondents : 



Henry A. Ward of Rochester, Addison E. Verrill of New Haven, 

 R. P. Whitfield of New York, Edgar A. Smith of London, August 

 Brot of Geneva, E. Ray Lankester of London, William E. Hoyle 

 of Edinburgh, Eduard von Martens of Berlin, William Kobelt of 

 Schwanheim, S. Clessin of Ochsenfurt, Rev. M. Heude, S. J. of 

 Zika-Wei, China, Rudolph Bergh of Copenhagen, A. T. de Roche- 

 brune of Paris and Herrman Friele of Bergen. 



The following were ordered to be printed : 



