INVERTEBRATES. 355 



the characters given by him, unless by the "thirteen to fourteen rather strong- 

 filiform striae" he mentions as ornamenting the whorls, he intends to convey 

 the idea that this is the entire number of these lines seen on any one whorl, 

 including those on the under side of the body volution ; in which case we 

 should scarcely entertain a doubt in regard to our shell being a distinct species, 

 since it uniformly has about double that number of revolving striae on the 

 last whorl. Dr. S. also describes the two sets of striae as "giving the surface 

 a handsome, crenulated appearance." The word " crenulated" here is probably 

 a misprint; at any rate it is not applicable to the species before us, the striae of 

 which are not crenulated, but form a neat, cancellated style of sculpturing haV - 

 ing much the appearance, as seen under a magnifier, of a piece of musquito 

 netting pasted upon a smooth surface. 



Should the shell under consideration prove to be distinct from that descri- 

 bed by Dr Shumard, which is not improbable, we would propose to designate 

 it by the name of Pleurotomaria intertexta. 



Locality and position: Hodge's creek, Macoupin county, Illinois; Lower 

 Coal Measures. 



Pleurotomaria tenuicincta, M. and "W. 



PI. 28, fig. 3 a, 3 6, 3 c, 3 d. 



Pleurotomaria tenuicincta, Meek and Worthen, October, 1860. Proceed. Acad. Nat. 

 Sci., Philad., p. 459. 



Shell small, conical-ovate; spire moderately elevated; volu- 

 tions seven, obliquely flattened or concave above, convex and 

 more or less distinctly angular around the middle, last one 

 prominently rounded below; suture distinct; spiral band very 

 narrow, concave, located a little above the middle of the 

 body whorl, and passing around rather below the middle of the 

 others ; aperture apparently subcircular ; umbilical region 

 indented, but apparently not distinctly perforated. Surface 

 ornamented by about fifteen to twenty, rather distinct revolv- 

 ing lines, only two or three of which occupy the flattened or 

 concave upper slope above the band, where they are less promi- 

 ment than the others ; while the two forming the margins of 

 the band are more salient than any of those below. Fine, 



