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



55 a. P. univittatum, Lea. 



Trypanostoma univittatum, LEA, Proc. Acad. Nat. Sci., p. 113, 1864. Jour. Acid. 

 Nat. Sci., vi, p. U5, t. 23, f. 58, 1837. 



Description. — Shell obtusely carinate, pyramidal, somewhat thick, 

 pale olive, shining, with a single band ; spire elevated ; sutures 

 impressed ; whorls flattened ; aperture rather small, rhom- 

 '^■'' boidal, whitish within, obscurely single-banded ; outer lip 



acute, much curved ; columella thickened below and very 

 much twisted. 

 Habitat. — Cahawba River, Alabama. 

 Diameter, -45; length, 1-2 inches. 



Observations, — A single specimen was received by Dr. 

 Hartman from Dr. Showalter and kindly lent to me for 

 description. It seems to be most nearly allied to T. Anthonyi 

 (nobis), but it is a smaller species, without the striffi and obscure 

 sulcations of that species, and it has a band which I have never 

 observed in Anthonyi, and probably a less number of whorls. It is 

 also somewhat allied to Hartmanii (nobis), but not so elevated, and 

 it is smaller. When Hartmanii is banded, it always has, I believe, 

 two. This specimen of nnivittatum has a single band above the 

 periphery which is observable on all the whorls above. The apex 

 being eroded, I cannot state the number of whorls, but they seem to 

 be about eight. The aperture is about one-third the length of the 

 shell. — Lea. 



Certainly very closely allied both to subrobustum and 

 Christyi. 



55 b. P. pallidum, Lea. 



Trypanostoma pallidum, Lea, Prop,. Acad. Nat. Sci., p. 174, 1862. Jour. Acad. Nat. 

 Sci., v, pt. 3, p. 275, t. 36, f. 30. Obs., ix, p. 97. 



Description.— ShcW smooth, attenuately conical, rather thick, pale 

 horn-color; spire very much raised; sutures very much impressed; 

 whorls eleven, slightly convex, somewhat geniculate above; aperture 

 rather small, subrhomboidal, Avhite within; outer lip sharp, sinuous; 

 columella white and very much twisted. 



Operculum subovate, light chestnut-brown, with the polar point ou 

 the left near the basal margin. 



