PLA.TE XIV. 



Oriskania navicella, Hall. 



Page 371. 



Figs. 1, 2, 3. Dorsal, profile and ventral views of the exterior; showing the 

 elongate form and plano-convex contour of the species . 

 Oriskany sandstone . Rondout, N. Y. 



CrYPTONELLA SUBELLIPnCA, Hall. 

 Page 371. 

 Figs. 4, 5, 6. Ventral, profile and dorsal views of an internal cast in iron-stone ; 

 showing the form and contour and the muscular scars of the brachial 

 valve. 

 Waverly group . Sciotoville, Ohio . 



Beecheria Davidsosi, Hall. 

 Page 372. 



Fig. 7. The internal cardinal structure exposed by the removal of a portion of 

 the pedicle-valve; showing the absence of dental plates and the structure of 

 the loop. X 3. 



Fig. 8. OutUne profile showing the manner in which the lamellae of the loop 

 originate from the hinge-plate . 



Fig. 9. Dorsal view of an elongate shell. 



Figs. 10, 11. Profile and dorsal views of an average specimen. 

 Carboniferous limestone. Windsor, Nova Scotia. 



DiELASMA OBOVATUM, Hall. 



Page 372. 



Figs. 12, 13, 14. Ventral, dorsal and profile views of the original specimen. 

 Coal Measures. Kentucky, 



Renssel^ria ovulum, Hall. 

 Page 370. 



Fig. 15. An internal cast of the brachial valve; showing the muscular scars, 

 the large cavity left by the hinge-plate and the genital workings in the 

 umbonal region. 

 Fig. 16. An internal cast of the pedicle-valve. 

 Oriskany sandstone . Cayuga, Ontario. 



402 



