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PLATE 50 



Wilsonia wadei Dunbar 

 Page 195. 

 Figs. 1, 2. Ventral and side views. 

 Figs. 3, 4. Dorsal and anterior views. 



Rhynchonella transversa Hall 

 Page 195. 



Figs. 5-12. Dorsal, side, ventral, and anterior views of two specimens. 



Figs. 13-15. Dorsal, side, and ventral views. 



Fig. 16. Dorsal view. 



Fig. 17. Side view. 



Fig. 18. Posterior view. 



Fig. 19. Ventral view. 



Fig. 20. Side view. 



Rhynchonella (?) bialveata Hall 

 Page 195. 



Figs. 21-23. Ventral, dorsal, and side views of one specimen. 

 Fig. 24. Dorsal view of the other observed specimen. 



Rensselaerina medioplicata Dunbar 

 Page 196. 



Figs. 25, 26. Dorsal and anterior views of the one specimen. 



Atrypina imbricata (Hall) 

 Page 197. 



Figs. 27-29. Side, ventral, and dorsal views of the single specimen. 



A try pa reticularis (Linne) 

 Page 198. 



Fig. 30. An incomplete, elongate ventral valve. 



Fig. 31. Internal cast of a ventral valve. 



Fig. 32. Posterior view. 



Figs. 33, 34. Ventral and anterior views. 



Fig. 35. Side view of an incomplete shell with numerous growth lines. 



Fig. 36. Anterior view of a specimen that shows the remains of fringes. 



Fig. 37. A dorsal valve that shows the remains of fringes. 



Fig. 38. An incomplete ventral valve that retains the remnants of fringes. 



Fig. 39. Anterior view of a specimen with a prominent dorsal fold. 



Fig. 40. Anterior view of a variety. 



Delthyris perlamellosus (Hall) 

 Page 199. 

 Fig. 41. Ventral view. 

 Figs. 42, 43. Dorsal and side views. 

 Figs. 44-49. Dorsal, side, and anterior views of two specimens. 



