PLATE 53 



Meristella laevis (Vanuxem) 

 Page 202. 



Figs. 1,2. Dorsal and side views. 



Meristella bella Hall 

 Page 203. 



Figs. 3-6. Ventral, dorsal, side, and anterior views of the single specimen. 



Meristella atoka Girty 

 Page 204. 



Figs. 7-10. Dorsal and side views of two specimens. 



Figs. 11, 12. Dorsal and anterior views. 



Figs. 13-15. Side, dorsal, and anterior views of a partially restored shell. 



Fig. 16. Dorsal view of an almost completely exfoliated individual. 



Fig. 17. An incomplete ventral valve. 



Fig. 18. Internal cast of a ventral valve. 



Fig. 19. A partially exfoliated ventral valve. 



Fig. 20. Anterior view of an almost wholly exfoliated individual. 



Rensselaerina medioplicata var. latior Dunbar (?) 

 Page 197. 



Figs. 21, 22. Dorsal and side views of a portion of a shell. 

 Fig. 23. A portion of a ventral valve. 



Fig. 24. Side view; the marked projection of the ventral above the dorsal beak is due 

 to distortion. 



