200 SMITHSONIAN INSTITUTION 



convex sides and beveled edges. In order to show the actual proportions of this unique 

 specimen, I have given a restoration of the crown from careful measurements of the parts 

 visible, figure 24b. 



The name of this species is given in honor of Mr. Kenneth M. Chapman, of Santa Fe, 

 New Mexico, the artist to whose great skill is due the majority of the fine illustrations accom- 

 panying this work. 



Type. Author's collection. 



Horizon and locality. Lower Carboniferous, Upper Burlington limestone ; Burlington, 

 Iowa. 



