PLEUKOCERA. 123 



except the lower whorl. The figure is from Mr. Anthony's 

 type. 



The following is Mr. Lea's description of 



Trypanostoma cornenm. — Shell striate, exserted, thin, semi-trans- 

 parent, pale horn-color; spire raised; sutures regularly impressed; 

 whorls eight, somewhat convex ; aperture elongate, narrow, elliptical, 

 whitish within; outer lip acute and very sinuous ; columella thin and 

 twisted. 



Habitat. — Tennessee. 



Diameter, -27; length, -76 inch. 



Observations. — Two specimens were sent to me some years since by 

 Mr. Anthony. I do not know from what part of Tennessee rig-232, 

 they came. In these two specimens, all the whorls but the 

 body-whorl have six or ten transverse strije. The base is pro- 

 longed almost into a channel, and thus approaches the genus 

 lo. In outline and color it is allied to T. venitsttim, herein 

 described, but diflers in not being fusiform, in having a larger 

 aperture, and in having striae. The aperture is more than one-third 

 the length of the shell. — Lea. 



Either Mr. Anthony sent these specimens before describing 

 altipetum^ or else he must have forgotten his own species. 



65. P. Ocoeensis, Lea. 



Melanin Ocoeensis, Lea. Philos. Proc. ii, p. 13, Feb., 1841. Philoa. Trans., viii, p. 

 1G9, t. 5, f. 13. Obs. iii, p. 7. DeKay, Moll. X. Y., p. 94. Tkoo.st, Cat. Shells 

 Tennessee. Buot, List, p. 38. Wiieatley, Cat. Shells U. S., p. 2G. Catlow, 

 Couch. Xomenc. p. 188. 



Melania Ocoeensis, Lea,BiNNEY, Check List, No. 1G6. 



Potadoma Ocoeensis, Lea, Chent, Man. do Conch., i, f. 1969. 



Potadoma Ocoiiensis Lea, Adams, Genera, i, p 21)9. 



Description. — Shell smooth, conical, somewhat thick, dark horn- 

 colored ; spire obtuse, towards the apex lined ; sutures im- 



Fig- 233. T , , 



pressed; whorls somewhat convex; aperture small, ovate, 



bluish. 



Habitat.— Ococc District, Tennessee; Dr. Troost. 



Diameter, -32; length, -92 of an inch. 



Observations.— Tivc specimens are before me, all of which 

 are more or less decollate. None of them have bands. 

 Oblique, irregular striae may be observed more or less on all 

 those which 1 have examined. — Lea. 



