PLATK XXI. 



PAUE. 



SCHIZODUS ULBICHI Worthen 110 



Fig. 1. Cast of right valve showing anterior muscular scar. 

 Fig. 1 a, h. Interior of valves showing cardinal tooth and socket. 



CLINOPISTHA BADIATA Hall, sp 12! 



Fig. 2. Ventral view, showing the gament. 



MACEODON SANGAMONENSIS Win-then l'> 



Fig. 3. View of right valve, natural size. 

 Fig. 8 a. Dorsal view of same. 



AVICULOPECTEN PBOVIDENBI8 C-OX, sp 11 



Fig. 4. View of left valve, natural size. 

 Fig. 4 a. Lateral view of same in outline. 



AVICULOPECTEN CHESTEBENSIS Worthen 11"> 



Fig. 5. View of a right valve, natural size. 

 Fig. 5 a. Lateral view of same in outline. 



