NATURAL SCIENCES OF PHILADELPHIA. 149 



feria^ Berendtia^ and, as stated above, some species now included 

 in Bulimus, Cochlostyla, Bulinuniis, Limicolaria. 



(c) Jaw with separate, delicate ribs, usually running obliquely 

 towards the centre: Gseotis^^ Amphibulima,^ Bulimuliis^ Gylin- 

 drella, Macroceramus,^ Pineria,'^ Partula.' 



Tile genera whose jaw is in one piece with an accessory qnad- 

 rate piece are Succinea^^ Omalomjx^^ Hyalimax,^" Athoracojjhorus.^^ 



The genei'a whose jaw is in sepai'ate pieces are Orthalicus, 

 Liguus, and Punctum.^'' I have arranged the American genera in 

 the same manner in the following pages. 



Bibliography. 



The principal works referred to are : — 



Leidy in Binney's Terrestrial Air-breathing Mollusks of the 

 United States. Boston, 1851, Little & Brown. The wood-cuts 

 of lingual membranes are misplaced in the text. See the list, vol. 

 II. p. 358. 



BiNNEY and Bland. Land and Fresh Water Shells of North 

 America. Part I. Smithsonian Miscellaneous Contributions. 

 Washington, 1869. 



Morse in Journal of the Portland Society of Natural History, 

 1864. 



Moquin-Tandon. Histoire Natnrelle des Mollnsques Terrestres 

 et Fluviatiles de la France. Paris, 1855. 



Fischer et Crosse. Etudes sur les Mollusques Terrestres et 

 Fluviatiles du Mexique et I'Amerique Centrale. Paris, I81i. 



Lehmann. Die lebenden Schnecken und Muscheln der Umger 

 gend Stettins und in Pommern. Cassel, 1873. 



' Morch, Journ. de Conch., 1865, 385. 



* Crosse and Fischer, Journ. de Conch. 1870, pi. V., fig. 11, 12. 



3 Bland and Binney, Ann. Lye. N. H. of N. Y., Vol. X., pi. XI., figs. 

 1, 5-7. 



< Proc. Phila. Ac. N. Sc. 1874, pi. VIII., figs. 2, 5, 6. Pellicula is a 

 synonym of this. ^ See this paper. 



6 Bland and Binney, Ann. N. Y. Lye. N. H., X., 33. 



7 Binney, Ann. Lye. N. H. of N. Y., XL 45. 



8 See tbis paper. s Malak. Blatt. X., pi. IV., fig. 5, a. 

 10 Fischer and Crosse, Journ. de Conch. XV., 318, pi. X., figs. 5, 7. 



" Bergh, verh. kais. kffinig. zoolog. botau. Gesell. in Wien. XX. 844, pi. 

 XII., fig. 2, 4, 5. '2 See tbis paper. 



