130 LAND AND FRESII-AVATER SHELLS OF N. A. [pART IV. 



74. p. modestum, Lea. 



Trypanostoma modestum, Lea, Proc. Acad. Nat. Sci., p. 174, 1862. Jour. Acad. Nat. 



Sci., V, pt. 3, p. 276, t. 36, f. 92. Obs. ix, p. 98. 

 Trypanostoma Knoxense, Lea, Proc. Acad. Nat. Sci., p. 175, 1862. Jour. Acad. Nat. 



Sci., V, pt. 3, p. 281, t. 36, f. 101. Obs. ix, p. 103. 



Description. — Shell smooth, conical, rather thin, greenish horn- 

 color; spire somewhat raised; sutures linear; whorls about seven, 

 somewhat convex, the last somewhat compressed; aperture rather 



small, subrhomboidal, bluish-white witMu; outer lip acute, 

 Fig. 243. 



sinuous, expanded; columella slightly thickened below and 



twisted. 

 Habitat. — Chilogita Creek, Blount County, Tennessee , J. 



Clarke. 

 Diameter, -32; length, -80 inch. 



Observations. — I have had a number of this species for some 

 years and had considered it a variety of Melania {Goniobasis) dubiosa 

 (nobis), but the difference in the outer lip, which is much more 

 expanded and some other characters, render it specifically different. 

 The expanded outer lip, which is slightly thickened towards the edge, 

 resembles that of Whitei, herein described, but it has a longer channel 

 and is not so truncate at the base. It also differs in being a shorter 

 species with a less number of Avhorls. None of the specimens before 

 me have bands. There is a disposition on the apical whorls to be 

 carinate. None of the specimens were perfect at the apex. Every 

 one was purplish above. The aperture is about one-third the length 

 of the shell. It is a very different shell from Melania QGoniobasis) 

 modesta (nobis). — Lea. 



Figured from Mr. Lea's plate. 



The followiug is evidently the same species. 



T. Knoxense. — Shell smooth, conical, ferruginous or banded, rather 



thick, spire rather attenuate, pointed ; sutui'es impressed ; 



Fig. 244. 

 whorls eight, slightly convex, carinate above; aperture small, 



white or brown within; outer lip sharp, sinuous, expanded; 



columella slightly thickened and twisted. 



Habitat. — Flat Creek, Knox County, Tennessee; Prof. D. 

 Christy. 



Diameter, 'SI ; length, -"G inch. 



Observations. — About a dozen of this little species were sent to me 



