8 BULLETIN NO. 2. 



these reports, page 381. PL 31. fig. 14. a, b, c, but differs from 

 that, in its surface ornamentation and its spiral angle. 



Position and locality: Coal Measures, Peoria county, 111. 



No. 2533 of the Illinois State collection. 



Collector, Mr. Gifford. 



GENUS TEACHYDOMIA, Meek and Worthen. 



TKACHYDOMIA NODULOSA. (sp. nOV.) 



Shell of medium size, obliquely ovate or sub-rhomboidal in out- 

 line, volutions four, the last one comparatively large and com- 

 prising more than two-thirds the entire length, rounded below 

 and slightly flattened above to the nearly perpendicular lower 

 border of the rather deeply impressed suture. Aperture nearly 

 sub-ovate with a well defined notch at its lower extremity; lip 

 sharp, columella flattened and smooth ; surface thickly covered 

 with prominent rounded nodes that are largest on the upper edge 

 of the volution, and increase in number as they decrease in size 

 towards the umbilical region. The nodes become obsolete on the 

 lower extremity of the last volution, leaving a limited space around 

 the lip that is ornamented only with a few rather coarse lines of 

 growth. 



Length of an average size specimen |f inch ; breadth -^jr inch. 



This shell is about midway in form and size between 2\ Whceleri, 

 and T. Hollukiyi, but differs from both in the form of its aper- 

 ture, and from the latter also in its more numerous and differently 

 formed nodes. 



Position and locality: Coal Measures, Peoria county. 111. 



No. 2538 of the Illinois State collection. 



Collectors, W. H. Adams and Mr. Gifford. 



GENUS BELLEROPHON, Montfort. 



BELLEROPHON GIGANTEUS. (sp. nOV.) 



Shell very large, sub-globose ; volutions expanding rapidly, roun- 

 ded over the dorsum and sides ; umbilical region deeply excavated. 

 Aperture reniform or sublimate, mesial band not shown on the 

 cast. Fragments of the shell adhering show that it was com- 

 paratively thick. 



Greatest breadth of the aperture about 4 inches ; height of the 

 same 2} inches; length from front to back 3j| inches. 



This shell is only known from a cast in limestone, but it may 

 be readily distinguished l>y its size and general form from all 

 known American species. 



Position and locality: Lower Coal Measures, Monroe county, 

 111. 



No, 2543 of the Illinois State collection. 



Collector, A. H. Worthen. 



