204 GASTBEOPODS. 



the columella curved, abbreviated or truncated at the base ; 

 the inner lip often well denned anteriorly, and usually sepa- 

 rated from the outer by a more or less well-marked notch ; 

 surface smooth ; accordingly, this group would include not 

 only those forms originally comprehended under Biilimella, 

 but also the species hereafter enumerated, and perhaps a few 

 others now known under other generic titles. 



Since then, it is manifest that Polyphemopsis is not cor- 

 rectly applicable to any known American gasteropods, and in- 

 asmuch as Biilimella of Hall had been used by Pfeiffer, it is 

 necessary to find some more appropriate term to designate t his 

 group. Bulirnorpha, established by Whitfield, is apparently 

 the only available name for the shells in question, but whether 

 this title will eventually be considered valid cannot now be 

 decided. 



Bulirnorpha bulimiformis (HALL). 



BulimeUa bulimiformis Hall, 1858 : Trans. Albany Inst., vol. IV, p. 29. 

 Polyphemopsis bulimiformis Meek & Worthen, 1866 : Geol. Sur. Illinois, 



vol. II, p. 373. 

 Bulimorpha bulimiformis WhitfieJd, 1882: Bui. Am. Mus. Nat. Hist., vol. 



I, p. 74. 

 Bulimorpha bulimiformis Hall, 1883: Geol. Sur. Indiana, Ann. Kept, for 



1882, p. 366, pi. xxxi, fi^s. 37-39. 

 Bulimorpha bulimiformis Keyes, 1839: Proc. Acid. Nat. Sci., Phila., p. 300. 



Shell fusiform, with the spire occupying about half the 

 entire length ; volutions five to six, regularly convex, and in- 

 creasing in size rather rapidly, the last somewhat longer than 

 the spire. Aperture broadly lanceolate ; outer lip sigmoidal, 

 with a small notch anteriorly; columella somewhat bent and 

 truncated at the base. Surface smooth, but often showing 

 faint lines of growth. 



Horizon and localities. Lower Carboniferous, Saint Louis 

 limestone: Saint Louis. 



