THE NAUTILUS. 09 



it. The specimens are to be deposited iu the Museum of the 

 Academy of Natural Sciences for permanent exhibition. In order 

 that the collection may be a credit to the Association, none but the 

 finest kind of specimens will be accepted and the exact locality of 

 every specimen contributed, must be designated. The matter of 

 contributing to the collection, will be, of course, purely voluntary 

 on the part of members, but it is urged upon them to take an 

 interest in the matter, for two reasons, viz : 1st. A complete, special 

 collection of all the mollusca of the United States will be valuable 

 for purposes of reference, identification of species, settlement of 

 disputed nomenclature, classification, and general scientific interest. 

 2nd. It will be a work, which will redound to the credit of the As- 

 sociation, by showing what the members are capable of doing, Avhen 

 united in gathering material for a great National Collection. The 

 name and address of each donor will be attached to the cards upon 

 which the specimens will be mounted. Members, who are willing 

 to assist the project, will please let the President of the Association 

 know what specimens they can contribute to the collection. 



Inquiries have been made by members, as to the best general works 

 of reference in the study of conchology. We would reconnnend 

 Tryon's Structural and Systematic Conchology, Phila., 1884 and Dr. 

 Paul Fischer's Manuel de Conchyliologie, Paris, 1887. Both of them 

 are invaluable to the student. Any bookseller, in America can 

 obtain them. 



Mr. Henry Hemphill in his recent Catalogue of North American 

 Shells, suggests some startling changes in the nomenclature of Amer- 

 ican Helices — mainly in the proposed reduction to varietal rank of a 

 number of species recognized by Mr. Pilsbry and other authorities. 

 In Mr. Pilsbry's subgenus Polygyi-a (including Polygyra, Mesodon, 

 Triodopsis and Stenotrema) the following changes would be made if 

 Mr. Hemphill be correct : 



Andrewsi, W. G. B.^^var. albolabris, Say. 



appressa, Say=:var. palliata, Say. 



armigera, Ancey=^var. Columbiana, Lea. 



binominata, Tryon=var. devius, Gould. 



Dorfeuillana, Lea=var. Texasiana, Moric. 



exoleta, Binn.=var. albolabris. Say. 



