372 PALAEONTOLOGY OF ILLINOIS. 



Macrocheilus, (undt.) 



PI. 27, fig. 10. 



Of this shell we have only seen internal casts, none of which show the aper- 

 ture nor the columella; hence we cannot determine whether it is identical with 

 any of the described species or not. In form it seems to agree quite nearly 

 with M. jvimigenius, Conrad (sp.). The impression left by the columella, how- 

 ever, in the matrix, appears to show no traces of the obtuse fold seen on that 

 of Mr. Conrad's species. It may be a new species, but we have thought it 

 would be better not to propose a new name for it until other specimens can be 

 obtained for examination. • 



The appearance of an umbilicus in the figure is merely the cavity occupied 

 by the columella, the specimen being an internal cast, and the appearance of 

 fine, revolving striae on the body whorl, is an error in the engraving. 



Locality and position: Bridge north branch Saline river, Gallatin county, 

 Illinois; Upper Coal Measures. 



Genus POLYPHEMOPSIS, Portlock. 



Synon. — Buccinum (sp.), Sowerby, 1839. Alurchisons Sil. Syst., p. 642; (not Linnaeus, 



1758). 

 Polyphemus (sp.), Sowerby, 18 — . Geol. Trans. (2d ser.) vol. v, p. 492 ; (not 



Montfort, 1810.) 

 Tolypkemopsis, Portlock, 1843. Geo]. Londonderry, p. 415. 

 Bulimella, Hall, 1856. Trans. Albany Inst., vol. iv ; (not Pfeiffer, 1852). 



Shell subfusiform, spire more or less elongated, and usually 

 pointed at the apex; whorls flattened or somewhat convex, 

 last one moderately large, but not ventricose, generally forming 

 more than half the entire length, somewhat produced below ; 

 outer lip simple, thin and nearly straight; inner lip wanting 

 (or sometimes a little developed below, and winding around up 

 the columella, so as to pass out of sight opposite the middle of 

 the aperture ?) ; columella without folds or callosity, slightly 

 twisted or winding, curved outwards below to meet the outer 

 lip, at the connection with which it is usually truncated ; aper- 

 ture narrow subovate, in the typical species effuse, or slightly 



