Descriptions of New Fluviatile Shells. 



shoulder of the succeeding whorl so as to form a series of 

 steps to the sub-acute apex ; body whorl large, generally an- 

 gulated or distinctly ribbed at base, which is not much rounded ; 

 sutures impressed ; aperture subrhomboidal, whitish within ; 

 outer lip much bent forward towards the base ; columella 

 straight, produced into a narrow deep sinus, which is slightly 

 recurved. 



Length 0.85 inch (22 millim.). Diam. 0.42 inch (11 millim.). 



Length of aperture O.oO inch (8 millim ). 



Breadth of do. 0.20 inch (5 millim.). 



Habitat. Alabama. 



My cab. Cab. Lye. Nat. Hist., N. Y. B. W. Budd, M.D. 



Obs. Belongs to the group of which M. canaliculata may be 

 considered the type. It is, however, much less elevated than 

 M. canaliculata, has not the conspicuous grooving on the body 

 whorl as in that species, and its spire has the whorls flat instead 

 of exhibiting an obtuse carina, as described by Mr. Say ; a 

 sharp elevated carina at the base of the whorls closely overlies 

 the suture beneath; the extreme upper whorls having this 

 more distant from the suture become distinctly carinated. The 

 regular gradation of the whorls is its most distinctive cha- 

 racter. 



33. JUelania fastigiata. 



Plate III. Fig. 13. 



T. conica, glabra, crassa, vi rente; spira elevata, acuta ; anfr. 9-10, 

 primum subcarinatis, deinde planis, fusco-bifasciatis, ultimo trifasciato, in 

 medio carina angulato; suturis impressis, apertura rhomboidea, intiis 

 albida, fasciata ; labro valde sinuato, columella recta, in sinum pro- 

 fundum producta. 



Shell conical, smooth, moderately thick ; of a pale yellowish- 

 green color, ornamented with two distinct, distant, reddish- 



MARCH, 1854- 3 ASK. LYC. NAT. HIST., VOL. VI. , 



