06 PROCEEDINGS OF THE ACADEMY OF 



unusually deep, linear fissure ; the whorls are somewhat shouldered, though 

 not so much so as in many of the species ; the spiral whorls are furnished 

 with two broad bands, one near tbe top of each and the other widely separate 

 and near the succeeding whorl, being often half concealed by it ; there are 3 

 bands on the body whorl equidistant from each other ; compared with G. bul- 

 bosa, nob., which it most nearly resembles, it is longer, more linear, and has 

 not the rapidly attenuating spire of that species nor its roughly striate sur- 

 face. 



Gyrotoma ampla, Anthony. Shell smooth, ovate, rather thick, olivaceous; 

 spire not elevated, but acute ; whorls 6 7, subconvex ; sutures well defined ; 

 fissure broad, rather deep and waved; aperture moderate, elliptical, flesh 

 colored and banded within ; columella smooth, or slightly thickened only at 

 the fissure ; body whorl striate, and banded ; whorls of the spire not banded, 

 but having a thickened cord-like line near the suture. 



Length 11-14 in. Breadth 7-16 in. Length of aperture 7-17 in. Breadth 

 of aperture 4-16 in. 



Hab. Coosa River, Alabama. My Cabinet. 



Obs. A fine symmetrical species of this interesting genus which hitherto 

 has not been very productive in species. Compared with Schizostoma funicu- 

 latam, Lea, which it most nearly resembles, it is smoother, thinner, more 

 acute, and has not the double cord-like lines of that species. Most if not all 

 the species of Gyrotoma have the fissure gradually filled up behind as it is 

 pushed forward in the process of growth, by a cord-like line more or less pro- 

 minent, often so much so as to produce quite a shoulder at the suture, and 

 this species is so marked, but it has no cord-like line in the middle of the 

 body whorl as described in funiculatum. 



Gyrotoma salebrosa, Anthony. Shell fusiform, robust, thick, nodulous, of 

 a dusky olive color ; spire truncated, leaving scarcely more than the body 

 whorl, but indicating by traces on the truncation the loss of three or four 

 others ; fissure moderately open, waved, not deep ; body whorl, roughly nodu- 

 lous at the upper part and ornamented by three dark bands below ; aperture 

 ample, ovate, dusky within and bounded with three broad bands ; columella 

 deeply rounded, covered with a thick deposit of callus, white at its lower por- 

 tion, but tinged with dark brown at the fissures. 



Length of shell f in. Breadth of shell h- Length of aperture 9^-16. 

 Breadth of aperture 5-16. 



Hab. Coosa River, Alabama. My Cabinet. 



Obs. This species presents the unusual characteristic of a nodulous surface, 

 which character has not been observed in any species hitherto described by 

 any American author. These nodules are very conspicuous and much com- 

 pressed laterally, so as to present very much the appearance of coarsely folded 

 ribs, thus furnishing a close approximation to the original type from which 

 Swainson formed the genus ; on this account it becomes exceedingly interest- 

 ing, as indicating great variety in the specific forms of this genus, giving 

 assurance that among the many varied forms yet to be discovered we may at 

 last find the identical species sent by Rafinesque to Swainson. These com- 

 pressed nodules will at once distinguish it from all other species. 



Gyrotoma carinifera, Anthony. Shell conic, thick, dark brown ; spire 

 obtusely elevated, truncate, though not abruptly so, six whorls remain, one 

 or two having apparently been lost by truncation ; carinations elevated, sub- 

 acute and found on all the whorls, two on each of the spiral ones and three to 

 four on the body whorl ; fissure direct, broad, and moderately deep, extending 

 about l-5th around the shell ; sutures irregular, much modified by the carinae, 

 and often concealed in part by them ; aperture ovate and banded within ; 

 columella much rounded, callous at the lower part only ; outer lip irregularly 

 waved, its outline modified by the carina? on the body whorl. No sinus. 



[Feb. 



