INVERTEBRATES. 147 



This shell is about midway in form and size between T. 

 wbeeleri and T. hollidayi, but differs from both in the form of 

 its aperture, and from the latter also in its more numerous and 

 differently formed nodes. 



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



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



No. 2538 of the Illinois State Museum. 



