PLATE XXXIX. 



(Figs. 1-3 copies; 4-9, 39-41 by K. P. Whitfield; 10-14, 19-27. 29-31, 34-36, 42 by G. B. Simpson; 15-18, 28, 32, 33, 37, 



38 by £. Emmons.) 



Genus VERNEUILIA, gen. nov. 



Pago 5S. 



Vekneuilia CHEiEOPTERYX, de Vciueuil. 

 Figs. 1-3. Three views; showing the slig'ht asymmetry of the shell, and the trisulcate sai-face of each 

 valve. (After PE Vkrnkdil.) 



Middle Devonian. Paffrath, Germany. 



Genus AMBOCCELIA, Hall. 



Page 54. 

 Sefe Plate 29. 



Amboccelia umbonata, Coiiiad. 



Figs. 4-6. Three views of an average example ; showing the great convexity of the pedicle-valve, its me- 

 dian groove, and the depressed-convex, marginally concave brachial valve. 



Fig. 7. The interior of the pedicle-valve ; showing the elevated umbo, the thickened, unsupported teeth 

 and the partial tilling of the delthyrium. X 3. 



Fig. 8. The interior of the brachial valve ; showing the low cardinal pi-ocess, elevated crural plates, and 

 the four adductor scars. X 3. 



Fig. 9. A pre|>aration, showing the volutions of the spiral coils. X 3. 

 Hamilton shales. Western New York. 



AMBOCfELIA PLANOCONVEXA, ShlUlliird. 

 Figs. 10-12. Views of a rather large example ; showing the general form and contour of the valves. 

 Fig. 14. Posterioi- view of the same specimen ; showing the cardinal areas, the imperfectly developed 

 deltidial plates and chilidiuin X 3. 



Coal Measures. Sjyringfield, Illvrwi». 

 Fig. 13. A small individual. 



Fig. 15. Enlargement of the surface of the same specimen ; showing the short spinules. X 5. 

 Coal Measures. Manhattan, Kansas. 



Amboc(elia spinosa, sp. IIOV. 

 Fig. 16. The exterior of a bra<;hial valve. 

 Fig. 17. An enlargement of the surface ; showing the narrow, elongate depressions which were probably 



the bases of superficial spines. X 6. 

 Fig. 18. Internal cast of the same specimen ; showing the impression of the dental sockets and crural 

 plates, and the faint adductor scars. 



Hamilton group. Livonia Salt Shaft, iV. Y. 



Genus METAPLASIA, gen. nov. 



Page 5«. 



Metaplasia py.xidata, Hall. 



Fig. 19. Interior of a brachial valve ; showing the articulating apparatus, adductor scars and vascular 

 sinuses about the muscular area and over the marginal regions. X 2. 



Fig. 20. Posterior view of the same valve ; showing the width of the cardinal ai-ea, elevation of the cardi- 

 nal process and socket-walls, and the linguate extension of the median sinus on the anterior 

 margin. X 2. 



Fig. 21. Internal cast of the pedicle-valve ; showing the median fold, and the impressions of divergent, 

 probably vascular sinuses extending forward from the pedicle-cavity. X 2. 



Fig. 22. Interior of a portion of the pedicle-valve ; showing the narrow cardinal area, thickened teeth and 

 deep muscular scar. X 2. 



Oriskany sandstone. Cayuga, Ontario. 



Genus SPHtlFERINA, d'Orbigny. 



Page 51. 

 Se« Plates 29, 'M. 



Spiriferina, sp. ? 

 Fig. 23. Interior of a portion of the brachial valve ; showing the articulating apparatus and the divergent 



muscular ridges in the bottom of the valve. X 3. 

 Fig. 24. A portion of the interior of the })edicle-valve ; showing a highly developed delthyrial callosity 

 uniting the dental lamellie and supported by a median septum. X 2. 

 Chester limestone. Caldwell county, Kentucky. 



