BULLETIN NO. 2. 



Shell above the medium size, consisting of about four obliquely 

 flattened volutions, the lower one forming about half the entire 

 length. The periphery of the lower volution shows a flattened 

 space about a quarter of an inch in width that was probably 

 occupied by a spiral band. Form of aperture and surface marii- 

 ings unknown. 



Length of the three lower volutions If inches ; greatest breadth 

 1^ inches. 



No. 2493 of the Illinois State collection. 



Collector, A. H. Worthen. 



PLEUROTOMAEIA COXANA. (sp. nOV.) 



Shell large, broadly umbilicated, spire moderately extended, its 

 length being equal to about one-third the full length of the shell ; 

 volutions about four, strongly and evenly convex above, and in- 

 creasing gradually in size, the last one abruptly rounded below 

 into the umbilicus ; aperture apparently subovate. The specimen 

 is a cast in limestone, and the surface was probably nearly smooth, 

 as the fragments of the adhering test show no external markings. 



Length 2^ inches ; breadth If inches ; diameter of the last 

 volution 1^6 inches. 



Named in honor of Mr. L. A. Cox, of Keokuk, from whom the 

 specimen was received. 



Position and locality : Keokuk limestone, Keokuk, Iowa. 



No. 2547 of the Illinois State collection. 



Collector, Mr. L. A. Cox. 



GENUS POKCELLIA, Leveille. 



PORCELLIA PEOMENSIS. (sp. nOV.) 



Shell small, volutions about five, closely embracing and very 

 gradually enlarging, the last one marked by a narrow dorsal band, 

 defined by a sharp elevated ridge on either side. Outer volution 

 ornamented also with a row of about nine smpJl nodes on either 

 side, which are situated about one-third the distance from the 

 inner margin to the dorsal band. Umbilical depression broad and 

 shallow. 



The surface of the shell in some of our specimens is thickly 

 pitted with small round depressions that are plainly visible under 

 a good lens, but they may however be due to some secondary 

 cause. 



Greatest diameter of the shell ^ inch; transverse diameter of 

 the outer volution | inch. 



Position and locality: This rare and beautiful little shell was 

 found in the lower Coal Measures of Peoria county. 111. 



No. 2531 of the Illinois State collection. 



Collector, Mr. Gilford. 



