PLEUROCERA. 69 



tusely conical ; sutures irapi-essed ; Avliorls seven, slightly convex, 

 the last very large, corded on the periphery ; aperture large, rhom- 

 boidal, obscurely banded Avithin ; outer lip acute, sinuous ; columella 

 thickened below, with reddish spots at the base, and much contorted. 



Habitat. — Tennessee; Prof. Troost: Cumberland Eiver; C. T. 

 Downie : North Alabama ; Prof. Tuomey : Ohio River, at Cincinnati ; 

 U. P. James. 



Diameter, -38 ; length, -71 of an inch. 



Observations. — This is a short thick species with a fine natural 



olivaceous polish. A specimen from Prof. Troost has been in my 



possession many years, and is the most perfect. It has two obscure 



bands inside. Another I recently obtained from Dr. 



Fig. 134. 

 Ilartman, who received it from Prof. Tuomey. A third is 



an old ei'oded specimen, quite brown, sent by Mr. Downie. 

 After the above description was made, I received from Mr. 

 James four specimens, neither of them entirely mature, 

 which he took in the Ohio River at Cincinnati. Two only 

 have the ligatures round the periphery of the last whorl. 

 Two have four bands, one has two well-defined bands and two are with- 

 out. One of the two without bands is of very dark brown, and the 

 other very light brown. The aperture is nearly one-half the length of 

 the shell. The obsolete bands within are dark brown, but the spot at 

 the base of the columella is of a bright reddish color. The upper part 

 of the whorls, which are slightly rounded. Is of a yellowish color. 

 Very different from the description of Melania lir/ata, described by 

 Menke, Synopsis, 82. — Lea. 



12. P. affine, Lea. 



Trypanostoma affine, Lea, Proc. Acad. Nat. Sci., p. 4, 18G4. Jonr. Acad. Nat. Sci,, 

 vi, p. 115, t. 23, f. 57, 1807. 



Description. — Shell channelled, pyramidal, horn-color; spire very 

 much raised ; sutures regularly impressed ; whorls about nine, chan- 

 nelled, flattened above; apert«re subrhomboidal, whitish or banded 

 within; outer lip acute, sigmoid; columella thickened and very much 

 twisted. 



Habitat. — Smith's Shoals, Cumberland River, East Tennessee. 



Diameter, -60; length 1-35 inches. 



Observations. — This species is allied to Thorntonii (nobis), and be- 

 longs to the group of whicli canaliculatnm, Say, may be considered 



