376 PALAEONTOLOGY OF ILLINOIS. 



prominent around the middle, somewhat extended below; suture 

 moderately distinct between the lower whorls, but scarcely 

 impressed above. Aperture rather narrow-subovate, acutely 

 angular above, narrow and apparently somewhat effuse below; 

 outer lip thin, sharp, and nearly straight ; inner lip somewhat 

 reflexed below, and winding around the columella so as to pass 

 out of sight opposite the middle of the aperture; obsolete above; 

 columella arcuate and tortuous, curving outwards to connect 

 with the outer lip at the base of the aperture. Surface smooth, 

 but showing under a good lens extremely fine, very obscure 

 striae of growth. Length, 1.67 inches; breadth, 0.54 inch; 

 apical angle regular, divergence 22°. Length of aperture, 

 0.55 inch; breadth of ditto, 0.30 inch. 



We have seen this beautiful species in collections labeled Loxonema Hallii. 

 A single glance, however, at the figure and description of that species published 

 by Norwood and Pratten (Joar. Acad. Nat. Sci., Philad., vol. iii, p. 77, pi. ix, 

 fig. 11), will be sufficient to satisfy any one that it is a clearly distinct species. 

 Norwood and Pratten represent their species as having the upper edge of the 

 whorls tumid, and separated by a deep suture ; while all the volutions in our 

 shell are nearly or quite flat, with a very shallow suture between. It also has 

 three or four more whorls and a totally different formed aperture — that of L. 

 Hallii being "three times as long as broad," while in our species it is scarcely 

 twice as long as wide. Our shell has likewise a much more arcuate columella, 

 while its body whorl is convex, instead of concave, around the middle. 



We have not seen a specimen of this species with the lip entire at the base 

 of the aperture. In our figure 7 b it was restored in outline below, but it is 

 there shaded in the engraving so as to give it a somewhat unnatural appearance. 

 As near as we can determine from the direction of the lines of growth, there is 

 not a truncation of the columella below, though we have not been able to see 

 exactly how it connects with the outer lip. In the figure, the engraver has 

 also carried the inner lip too far up. It is not developed above the middle of 

 the aperture, where it passes around out of sight. 



Locality and position : Near Urbana, St. Clair county, Illinois ; Upper Coal 

 Measures. Also, near Springfield, in same position. 



