PLFXROCERA. 49 



Subgenus PLEUROCERA, Rafinesque. 



Pleurocera, Rafinesque, Jour, de Pliys. Bruxelles, tome 88, p. 423, 

 1819. Blainville, Diet. Se. Nat., xxxii, p. 23G, 1824, xli, p. 376, 

 1826, Man. Malacologie, p. 441, 1825. Kaug, Mau. Conchy]., p. 

 374, 1829, Menke, Syn. Method, 2d edit., p. 43, 1830. Feuussac, 

 Bull. Zool., p. 93, 1835. Sowerby, Conch. Man., 2d edit., p. 231, 

 1842. IIermanxson, Indicis Gen. Malacoz., i, p. 296, 1846. 

 IIaldeman, Iconog. Encyc, p. 84. 



Ccriphasia, Swainson, Malacol., pp. 204, 342, 1840. Gray, Syn. 

 Brit. Mus., 1844. IIermann.son, Indie. Gen. Mai., i, p. 208, 1846. 

 Gray. ZooI. Proc., pt. 15, p. 153, 1847. II. and A. Adams, Gen- 

 era Recent Moll., i, p, 297, 1854, Chenu, Manuel de Couchyl, 

 i, p. 288, 1859. 



TelescupcUa, Gray, Proc. Zool. Soc, pt. 15, p. 153, 1847. 



EHmia (part), II. and A. Adams, Genera, i, p. 300, 1854. Ciienu, 

 Man. de Conchyl., i, p. 290, 1859. 



Merjara (part), H. and A. Ada.ms, Genera, i, p. 306, 1854. Ciienu, 

 Man. de Conchyl., i, p. 293, 1859. 



Tri/panostoma, Lea, Proc. Acad. Nat. Sci., p. 169, April, 18G2. Jour. 

 Acad. Nat. Sci., 2d ser., v, pt. 3, p. 2G8, March, 18G3. Obs., ix, 

 p. 90, INIarch, 18G3. 



Melanin (sp.), of authors. Binney, Check List. Reeve, Jlonog, 

 Mel., Nov., 1859, to June, 18C1. Brot, Cat. Syst., p. 30, 18C2. 



Description. — Shell generally lengthened conical or cerith- 

 ifonn, aperture moderate, prolonged into a short spout or 

 canal in front. Columella not callousl}' thickened. 



Geographical Distribution. — The species contained in this 

 subgenus are inhabitants of the valleys of the Ohio, Ten- 

 nessee and Alabama rivers. Two or three species are found 

 as far north as the Great Lakes, but none, so far as I am 

 aware, have been found in any of the rivers of the Atlantic 

 seaboard, or west of the Mississippi. 



The species generally have a wide distribution within the 

 limits referred to and are numerously represented in individuals. 



Mr, Lea has described several of the species as Jo's, but I 

 restrict the typical form of lo to the fusiform, veutricose 

 species, in which the canal and spire arc subequal. 



L. F, W, 8. IV. i 



