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290 NEW MELAtflDiE OF THE UNITED STATES. 



Shell carinate, subulate, rather thin, horn-color; spire attenuately conical; .sutures 

 very much impressed ; whorls ten, flattened below and carinate above ; aperture 

 small, subrhomboidal, whitish within; outer lip acute, sinuous; columella slightly 

 thickened and twisted. 



Operculum ovate, dark brown, with the polar point near the base slightly on the 



left. 



Proc. Acad. Nat. Sci., 1862, p. 174. 



Bab. — Knoxville, Tennessee, Prof. Troost and W. Spillman, M. D. 



My cabinet and cabinets of Dr. Troost and Dr. Spillman. 

 Diam. -39, Length 1-07 inch. 



Remarks. — This species is nearly allied to Melania (Th-ypanostoma) bicostala, Anth., 

 and in outline and size very close to Melania {Tnjpanostoma) Ocoeensis (nobis). From 

 bkostata, it may be distinguished by the difference in the aperture, in being more sub- 

 ulate, and in having the carina less marked. The channel of bicostata is more retrorse 

 and more angular at the point. The aperture is about one-fourth the length of the 

 shell. Two of the three specimens before me are without any bands, the third has a 

 well-defined brown band within the aperture. It is nearly the same in outline as alien- 

 uatum herein described, but differs in the form of the aperture and in being carinate. 



Tkypanostoma olivaceum. PL 36, fig. 117. 



Testa carinata, subfusiformi, subcrassa, olivacea; spira subobtusa; suturis impressis; anfractibns instar 

 octonis, planulatis ; apertura subgrandi, rhomboidea, intiis albidii; labro aouto, sinuoso; columella in- 

 terne incrassata et valde contorts. 

 Shell carinate, subfusiform, rather thick, olivaceous ; spire rather obtuse ; sutures 

 impressed ; whorls about eight, flattened ; aperture rather large, rhomboidal, whitish 

 within ; outer lip sharp, sinuous ; columella thickened below and very much twisted. 



Operculum ovate, dark brown, with polar point near to the base. 

 Proc. Acad. Nat. Sci., 1862, p. 172. 



Hah. — Tombigbee Kiver, Mississippi, W. Spillman, M. D. 



My cabinet and cabinets of Dr. Spillman and Dr. Hartman. 

 Diam. -50, Length 1-06 inch. 



RemarJcs. — Dr. Spillman sent me quite a number of this species. In outline and 

 size it is very near to Strephobasis olivaria (nobis), but it differs in the base of the col- 

 umella, which separates it from the genus Slrejriiobasis, and it is more flattened on the 

 whorls, and is not banded ; except in rare cases it has an obscure small band near the 

 base. The olive-green hue of the epidermis is very constant. The carina generally 

 leaves a thread-like line along the suture. The aperture is about one-third the length 



of the shell. 



Trypanostoma moeifoeme. PI. 36, fig. 118. 



Testa sulcata, subcylindraeea, solida, uno-vittata, cornea, spira obtuse conica ; suturis impressis ; anfrac- 

 tibua instar novenis, impressis, canaliculars ; apertura parviuseula, rbombica, intiis alba, et uni- 

 vittata, ; labro acuto, valde sinuoso ; columella inferne incrassata et valde contorts. 



