PLATE 8. 



Pag*. 



Fig. 1. Pachymya atjstinensis 298 



a. Left valve, reduced to two-thirds of the natural diameter, from 



Dr. Shumard's figure. 



b. Natural cast ; dorsal view ; reduced one-half of the natural 



diameter from a specimen from Salado, Tex. 

 See, also, Plate 5, figs. 7 a and b. 



Fig. 2. Ostrea (Alectetonia) bellaplicata 276 



a. Exterior view of upper valve ; natural size. 



b. Interior view of the same. From photograph copies of Dr. 



Shumard's original figures. 

 See, also, Plate 4, figs. 3 a and b. 



Fig. 3. Ostrea quadriplicata 275 



a. Lower valve ; natural size. 



b. Upper valve. Both from photograph copies of Dr. Shumard's 



original drawings. 

 See, also, Plate 5, fig. 6 a. 



