19 



Synonymy of the species of STREPOMATIDJE, a Family of Fluviatile Mollnsca, 

 inhabiting North America. 



Parti. 

 BY GEORGE W. TRYON, JR. 



The following synonymy of the very numerous species of North American 

 shells, heretofore considered Melanians, is offered as the result of a year's 

 study of the extensive collections of the Smithsonian Institution and of the 

 Academy of Natural Sciences, as well as those of Messrs. Lea, Haldeman, 

 Anthony, and Gould, together with my own, and several smaller collections. 



The present publication is preliminary to that of a complete illustrated 

 Monograph of the Family, prepared at the request of the Smithsonian Insti- 

 tution, (the MSS. of which is nearly completed) ; and is intended to i nvite 

 criticism. 



Naturalists are requested to communicate to the author, without delay, any 

 information they may possess regarding any of the species. 



As many of these species, being rare, have not been sufficiently studied to 

 determine satisfactorily their true position with regard to allied forms, or in 

 other words, their range of variation, it is particularly requested that Natur- 

 alists residing near localities inhabited by the Strepomatidce, would collect 

 and transmit to the Smithsonian Institution, extensive suites of specimens, 

 for which, if desired, a named suite will be returned. 



Family STREPOMATIDJE, Haldeman. 



Strepomatidce, Hald., Froc. Acad. Nat. Sci., Sept. 1863. 



Melaniana, Lam., Extr. d' un Cours., 1812. Hist. Anim. Sans. Vert., vi. p. 



163, 1822. Edit. 2, viii. p. 425, 1838. Deshayes, Encyc. Meth., iii. p. 



431 and 553, 1832. Reeve, Zool. Proc., p. 76, 1841. Conch. Syst., ii. p. 



119,1842. Sowerby, Conch. Man. , Ed. 2, p. 187, 1842. Catlow, Conch. 



Nomenc., p. 185, 1845. 

 Melanidez, (part) Latreille, Fam. Nat., 1825. Lea, Proc. Philos. Soc., iii. 



p. 164, 1843. 



Melaniance, (part) Swainson, Malacol, p. 198, 340, 1840. 

 MelaniadcR, (part) Gray, Syn. Brit. Mus., 1840. Turton's Manual, ed. 2, p. 



79, 85. Zool. Proc., part 15, p. 152, 1847. 

 Melaniidae, (part) Adams, Genera, p. 293, 1854. 

 Ceriphasince, Gill, Proc. Acad. Nat. Sci., p. 34. 35, Feb. 1863. 



Synopsis of Genera. 



A. Aperture produced into a more or less obvious canal in front. Trypanos- 

 tomoid Section. 



1. Shell fusiform, inflated, spire and canal 



produced, columella without deposit 



of nacre Genus Io, Lea. 



Shell conical or oval, canal not so 

 much produced Subgenus Pleurocera, Raf. 



2. Shell oval, or turbiniform, or fusiform, 



with a revolving row of nodules on 



the periphery, canal short. Colu- 

 mella callously thickened above and 



below Genus Angitrema, Hald. 



Shell oval or oblong, smaller, either 



smooth or adorned with nodules 



around the upper portion of the body 



whorl Subgenus Lithasia, Hald. 



Canal retrorse Subgenus Strep hob as is, Lea. 



