PSAM. 



786 



back, and front border ; 6 a immature large tooth, the inner 

 half preserving the beautiful rough crown surface; J, articu- 

 lar border. 8U Louis limestone^ at Alton, 111. — XI. 



Psammodus glyptus, St. John and Worthen Geo. Sur. 



111., Vol. 7, 1883, page 209, plate 14, figs. 5 «, J, <?, upper right 

 tooth, fragments showing rough crown surface; 5, back edge; 

 (?, articular or inner margin. (Omit figs. 6 a, 5, c). Cedar 

 Or., 111. Main fish-bed in Upper Burlington limestone. XI. 



Psammodus grandis, St. John and Worthen, Geo. Sur. 



111., Vol. 7, 1883, page 211, plate 15, figs. {1 a to d omitted); 

 2 a, lower tooth of a large fish, showing upper grinding sur- 

 face, worn with use; 5, back edge of it; c profile. (3 a^ J, c, 

 omitted). Keokuk limestone. XI. 



Psammodus lovianus, St. John and Worthen, Geo. Sur. 

 111., Vol. 7, 1883, page 207, plate 14, fig. 7a, lower tooth, crown 



