OP CONCHOLOGY. 115 



be aware of this, since, of the six species then described, he states 

 the aperture to be elliptical in five cases and rhornboidal in 

 the other, although his generic character is ' aperture ovate.' 

 Indeed, in the species described by him but a single one has 

 the aperture ovate, and that one is described as an Anculosa. 



"■ It may be doubted whether Mr. Lea's first name will not 

 eventually prevail, since, before he published Schizostoma^ 

 Bronu's genus of the same name (Lethea Geogn., i., 95, 

 1835-37,) had been called a synonym of Bifrontla [Omalaxis) 

 of Deshayes. (Vide Desh. in Lam, ix., p. 101.) Indeed, H. & 

 A. Adams (Gen. Rec. Moll., i., 305,) do not appear correct in 

 giving preference to Oyrotoma over Schizostoma, Lea, on ac- 

 count of Schizostoma, Bronn, since (on p. 244) the latter is 

 placed in the synonymy of Omalaxis. 



" Another generic name Schizostoma is quoted in Her- 

 mannsen's Index. I have not obtained access to the work 

 containing this description; but its date is said to be anterior 

 to Mr. Lea's description, 



" Mr. Lea's second name, Schizochilus, had been previously 

 used in Coleoptera, but withdrawn after Mr. Lea's description 

 was published. 



"Mr. Shuttleworth, in July, 1845, (Mittheilungen der Na- 

 turforschenden Gesellschaft in Bern, p. 88,) gives another 

 description of the genus under the name of Qyrotoma, 

 founded on two species from the Coosa River, descriptions of 

 which are also given. 



"The generic name of Mr. Shuttleworth has been adopted in 

 H. & A. Adams' Genera of Recent Mollusca (i. p. 305, February, 

 1854.) 



"Dr. Gray also (Guide to Mollusca, i. p. 103, 1857) adopts 

 Shuttleworth's name. 



Such being the confused state of the synonymy of the 

 genus, we have decided to adopt, at least temporarily, the 

 earliest name concerning which no doubt exists." 

 , To the above, Mr. Lea made the following reply, upon occa- 

 sion of describing some new species belonging to the genus, in 

 Proc. Acad. Nat. Sciences, Philada., May, 1860 : — 



"Genus SCHIZOSTOMA. 



"It will be ob.served that I have here adopted my first name 

 {Schizostoma) for the division of those Melanidse which have 

 a cut or fissure in the upper portion of the last whorl. This 

 name I proposed in December, 1842. Subsequently finding 

 that it was used by Bronn in 1835, I abandoned it, and pro- 

 posed the name of Schizochilus as a substitute, (Obs. on the 

 Genus Unio, v. 5, p. 51, 1852, and Trans. Am. Phil. Soc, 1852.) 

 I am now satisfied that Bronn's name was applied to the same 



