48 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



by the Gulf Stream. Among these may be mentioned Zonites gund- 

 lachi, Cylindrella poeyana, Bulimulus marielinus, Strophia incana, 

 Stenogyra subula and gracilima, Liguus fasciatus, Orthalicus undatus, 

 the two species of Macroceramus, from Cuba; Helix varians, from the 

 Bahamas; and Bulimulus multilineatus, from South America. Glan- 

 dina truncata is also a Cuban species, as well as Helix vortex and 

 Chondropoma dentatum. Of the West Indian shells, Strophia incana, 

 Bulimulus marielinus, the Stenogyras, Helix varians, Orthalicus unda- 

 tus, the Cylindrellas, and Chondropoma dentatum seem to be confined 

 to the lower Keys or the extreme southern portion of the peninsula; 

 Bulimulus multilineatus and Liguus fasciatus range farther north ; the 

 two species of Macroceramus extend to Tampa Bay; and the re- 

 mainder are probably found over the greater part of the State. Of 

 course these limits may be extended by future research. 



Third — The fresh-water species have but a small representation 

 from the tropics. Planorbus tumidus is a Cuban shell; so are Ampul- 

 laria depressa and Neritina reclivata. Ancylus obscurus is West 

 Indian, and Ampullaria caliginosa is from Mexico and Nicaragua. A 

 number of the univalves are of northern origin, no doubt: such as 

 Limnaea humilis, Planorbis trivolvis, Physa heterostropha, and the like. 

 The species of Unios are all, so far as I know, confined to the waters 

 flowing into the Atlantic and Gulf of Mexico, and many of them are 

 probably peculiar to the State. 



In the preparation of this catalogue, I have been continually under 

 obligation to Mr. William H. Dall, of the United States National Mu- 

 seum, at Washington. He has identified several hundreds of the 

 smaller and less known species, has aided me constantly with advice 

 and valuable suggestions, and has written out the descriptions of the 

 new species. To him my thanks are due for his patience and forbear- 

 ance throughout. Mr. Dall wishes me to say that he has simply given 

 a name to such species as have passed through his hands; that it would 

 be impossible to tell whether these names will stand or not when the 

 synonymy is thoroughly worked out. 



I would also express my obligations to Mr. John Ford, of the Phila- 

 delphia Academy of Natural Sciences, for comparing many of my spe- 

 cies with the type-shells in the museum, and for kindly help and en- 

 couragement; to M. C. F. Ancey, of Marseilles, France, for identifying 

 many of the land species and fresh-water univalves; to Mr. William A. 

 Marsh, of Aledo, 111., and Mr. Harry A. Pilsbry, of Davenport, Iowa, 

 for assistance in identifying the Unios. 



