IS DAVENPORT ACADEMY OF NATURAL SOIEN'CES. 



Mr. Pratt. He found it, with others, under an old log on Rock 

 Island, , 



Mr. Pratt exhibited large numbers of small 1)1 valve crustaceans 

 (related to Limnadea and Estheria) which he had collected dur- 

 ing the past week (since May 20th) in a pool of stagnant water 

 on Rock Island. There seem to be two or more species, differ- 

 ing in size and in other ways. The smaller variety is now much 

 more abundant than at first, thus giving rise to the idea that 

 they may be the young of the larger species, but this is doubt- 

 ful, for no intermediate stage is noticed. These animals are 

 very lively, and may frequently be seen in pairs, thus showing 

 them to be full grown. Associated with these crustaceans in 

 the same pool are found Limnma caperata^ Planorbis pai^vus^ etc. 

 The late Mr. A. U. Barler found a single specimen of a larger 

 species several years ago, in the river on the south shore of Rock 

 Island. Prof. Sheldon has had specimens of the dry shells of 

 probably two species in his collection for some years, but did 

 not know what they were. 



During the past week Mr. A. S. Tiffany collected two speci- 

 mens of Helix perspeotiva Say in a ravine near Rockingham. 

 One of these he has presented to the Academy. This makes 

 the third species added to the fauna of Davenport by Mr. Tif- 

 fany since the publication of Mr. Pratt's list. 



Mr. Pratt visited the slough back of Rock Island City on May 

 14rth and 21st. Here he collected Limnea reflexa and Physa 

 heterostropha in large numbers. This is the best locality for 

 these species he knows of in this vicinity. He also found man}^ 

 specimens of Planorhis [Menetus) exacutus — a species which he 

 had not previously collected, though it was included in the list on 

 Prof. Sheldon's authority. Associated with these were Planorhis 

 parvus, Segme?itina armigera, etc. Also one young specimen of 

 Yivipara intertexta, thus showing that this species still inhabits 

 this station though it had not before been collected there since 

 1870. This morning (May 27th) he again visited the Island 

 (Rock Island), and collected a few land shells — among them 

 several specimens of Helix clausa, a species he had not found 

 for several years, and never in any other locality. 



Mr. Pratt noticed a peculiarity in the habits of Bulinm hyp- 



