PLEUKOCERA. 



99 



Fig. 188. Fig. 189. 



40. P. aratum, Lea. 



Melania aratum, Lea, Pliilos. Proc. ii, p. 212, Dec, 1842. Philos. Trans, ix, p. 24. 



Obs., iv., p. 24. DeKay, Moll. X. Y., p. '.;S. Brot, List, p. 30. 

 Melania exarata, LEA, Philos. Proc. ii, p. 14, Feb., 1841. Philos. Trans., viii, p. 183, 



t. G, f. 44. Obs., iii, p. 21. TuoosT, Cat. Bixney, Check List, Ko. ICl. Cat- 



LCW', Conch. Xonienc, p. 186. 

 Ceriphasia exarata, Lea, Adams, Genera, i, p. 297. 

 Trypanostoma cinctunu'LF.A,'Proc. Acad. Nat. Sci., p. 112, 18G4. Jour. Acad. Xat- 



Sci., vi, p. 147, t. 23, f. CO, 1867. 



Description. — Shell carinate, conical, rather thick, black; sutures 

 rather deeply grooA'ed; whorls flattened, carinate ; 

 aperture small, at the base angular and channelled, 

 dark within. 



Habitat. — Tennessee. 



Diameter, -28 ; length, -57 of an inch. 



Observations. — I received oul}' two specimens of 

 this species, both of which are decollated. It is 

 perfectly distinct, and remarkable for its jetty hue, its carina and its 

 deeply impressed sutures, which are caused by the carina. — Lea. 



First described as e.xarata, which was preoccupied by Menke. 

 I suspect that this species is identical with PL gradatum, 

 Anthony, the latter being the adult form, TJie following is no 

 doubt identical. 



Fig. 1 



Trypanostoma cinctum. — Carinate, subfusiform, somewhat thick, 

 dark horn-color; spire somewhat raised; suture impressed; whorls 

 about seven, flattened; aperture rather small, rhomtaoidal, 

 whitish within ; outer lip a,cute and sinuous ; columella thick- 

 ened and twisted below. 

 Habitat. — North Alabama. 

 Diameter, -32 ; length, -05 inch. 



Observations. — A single specimen only was received, and it 

 was among several specimens of Alabamense (nobis), to which it is 

 allied ; but it is evidently a smaller species, -with a comparatively 

 shorter spire and with a more developed angle on the periphery, 

 which is accompanied by a furrow. The angle on the lower whorl 

 is cord-like, while on the upper whorls it is sharper and has the 

 furrow deeper above. There are no colored bands on this specimen, 

 and I suspect that it will be found to be generally if not always 



