284 NEW MELANIDJE OF THE UNITED STATES. 



Remarks. — This is the largest species of Trypanostoma of our country which I have 

 seen. It is nearly two inches long and is athletic. It is closely allied to Melania 

 ( Tnjpanostoma) canaliculata and undulata, Say, which two may indeed be only va- 

 rieties of each other. It has a carina like each of them, and this is sometimes slight- 

 ly nodulous like the latter, and there is a slight furrow-like impression above the ca- 

 rina which reminds one of the former. The whorls are remarkably flat and the color 

 of the epidermis is more brownish. Three specimens out of six before me are more 

 or less banded inside. The specimen from Tuscumbia is whitish inside and has two 

 indistinct bands. It is an imperfect specimen, and may really not belong to this spe- 

 cies. The aperture is more than one-fourth the length of the shell. 



Trypanostoma Thorntonii. PL 36, fig. 106. 



Testa carinata, pyraniidata, subcrassa, cornea, vel vittata vel evitatta ; spira regulariter elevata; suturis 

 paruin impressis; anfractibus instar denis, planulatis ; apertura parviuscula, rhoruboidea, intiis albida; 

 labro acuto, valde sinuoso ; columella inferno incrassa et valde contorta. 



Shell carinate, pyramidal, rather thick, horn-color, banded or not banded ; spire 

 regularly elevated ; sutures somewhat impressed ; whorls about ten, flattened ; aper- 

 ture rather small, rhombic, white within; outer lip acute, very sinuous; columella 

 thickened below and very much twisted. 



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

 Proc. Acad. Nat. Sci., 1862, p. 170. 



J2a&.-^-Tuscumbia, Alabama, L. B. Thornton Esq., and Rev. G. White ; Chatta- 

 nooga, Tennessee, J. Clark. 



My cabinet and cabinets of Mr. Thornton, and Dr. Hartman. 

 Diam. -62, Length 1*37 inch. 



Remarks. — -This appears to be a common species about Tuscumbia and up the Ten- 

 nessee River. I have about sixty specimens before me. They came with a large 

 number mixed up with Mel. (Trypanostoma) undulata, Say, but were easily separated 

 from that species. They are always smaller, and none have undulations. Like 

 undulata they are usually banded, only eight are without bands entirely. Some speci- 

 mens have a single broad revolving band on all the whorls, some have several 

 bands, and others again have a capillary line visible on the inside only. Four are 

 dark purplish green, the color being caused by the broad bands on the inside. It is 

 nearly allied to T. moriformi, herein described, but is not cylindrical. The specimens 

 are usually of a very regular pyramid with a short base. The carina of the periphery 

 is usually strong, but not always so. In this it is near to Melania (Tryponostoma) 

 filum (nobis), but it is more slender than that species. The aperture is about one- 

 third the length of the shell. Most of the specimens are slightly channelled on the 

 lower whorl. I name it after L. B. Thornton, Esq., to whom I am indebted for many 

 fine specimens of this and other shells. 



