44 Trans. Acad. Sci. of St. Louis. 



the whorl, the distance from center to center equal to about 

 ^ the diameter of the cross section of the shell at that point. 

 Surface marked by extremely faint revolving lines and by still 

 fainter transverse lines; neither of these are conspicuous, 

 however, and ordinarily the specimens appear to be smooth. 



Remai'ks. This species has been observed only in the form 

 of fragments, not a single specimen exhibiting a complete 

 whorl having yet been found. In all cases these fragments 

 are only one-half of the shell, as if the shell were split in the 

 plane of its coil, a manner of occurrence that would seem to 

 indicate that the shell was so constituted as to separate with 

 ease along the peripheral band. 



Four species of this genus have been recorded from the 

 Kinderhook of Iowa and Illinois, but three of these have never 

 been illustrated. The Northview shell differs from P. nodosa 

 Hall, in its more gradual increase in size and in its more fre- 

 quent nodes. It seems to approach nearest to P. recimocZa Win., 

 from the " Yellow Sandstone " at Burlington, Iowa, although 

 this species was but very briefly described and was never illus- 

 trated. The Northview shell differs from it in being larger, 

 and perhaps in other characteristics which cannot be deter- 

 mined certainly from the published description. From the 

 other two described species the Northview shell differs to such 

 an extent that no comparison need be made. 



LoxoNEMA sp. 



PI. V. f. 5. 



This species is represented by several more or less imper- 

 fect, elongate conical shells, with smooth, convex whorls and 

 moderately impressed sutures. It evidently belongs to the 

 smooth shelled division of the genus as described by De Ko- 

 ninck.* The specimens are not perfectly enough preserved 

 to allow specific identification or description, but in their 

 general form they resemble the Belgian species L. lefehvrei 

 L^veille.t 



Faun, du Calc. Carb. de la Belg. pt. 3. f Loc. cit. pi. V. f. 7. 



