274 LAND AND FRESH-WATER SHELLS OF N. A. [pART IV. 



subrhomboidal, at the base angular, within purplish ; columella pur- 

 ple and twisted. 



Habitat. — Branch of Coosa lliver, Alabama. 

 Diameter, -30; length, -84 of an inch. 



Observations. — A single specimen of this species Avas received from 

 Fie o-^Sa ^^^^- Brumby. It has the apex so much eroded as to present 

 only a little more than three whorls, which are, however, 

 perfect, and enable me to distinguish it from its allied spe- 

 cies, the nearest of which is M. arata (nobis). The sutures 

 have the same furrowed line, and the sides of the whorl are 

 alike flattened. The aperture, however, differs in form and 

 color. In the arata the columella is straiglit down to the 

 channel at the base ; in the fnrva, it is curved to the right and the chan- 

 nel is less marked. The length of the aperture, in perfect specimens, 

 must be about one-third the length of the shell. The Alexandrensis 

 (nobis) from Louisiana, is very closely allied to this species, and 

 when perfect specimens of both shall be obtained, they may possibly 

 be found to be the same. — Lea. 



175. G. dubiosa. Lea. 



Melania dtihia, Le\, Pliilos. Proc, ii. p. 11, Feb., 1841. 



Melania dubiosa, Lea, Pliilos. Trans., viii, p. IGG, t. 5, f. 6. Obs., iii, p. i. DeKav, 



Moll. N. Y., p. 93. BixxEY, Check List, No. ni. TuooST, Cat. Shells Tennes.sce. 



Wheatley, Cat. Shells U. S., p. 25. Jay, Cat. 4th edit., p. 273. Catlow, 



Conch. Nomenc, p. 183. Brot, List, p. 37. 

 Goniobasis Estabrooldi, Lea, Proc. Aciul. Nat. Sci., p. 2G4, 1862. Jour. Acad. Nat. 



Sci., V, pt. 3, p. 298, t. 37, f. 131, March, 1SG3. Obs., ix, p. 120. 



Description.— Shell smooth, conical, rather thin, horn-color; spire 

 rather elevated; sutures linear; whorls seven, somewhat convex; 

 aperture elliptical, small, subaugular at the base, whitish, yj^ 539. 



Habitat. — Tennessee; Dr. Troost. 



Diameter, -30 ; length, -75 of an inch. 



Observations. — This is a rather small species, somewhat 

 lijve M. simplex, Say, but seems to me to differ, iu having a 

 more elevated spire, and a smaller aperture. The aperture 

 is rather more than one-third the length of the shell. — Lea. 



Figured from Mr. Lea's plate. One or two specimens of 

 this species are plicate on the first two or three whorls, but 

 the plicai are by no means characteristic of the species. 



The following is a synonyme : — 



