PLATE XLIV— Continued. 



Meristella nasuta, Conrad. 



See Pliile 43. 

 Fig. 13. An internal cast of a peiiicle-valve ; showing the position of the teeth and the deep muscular im- 

 pressions. 

 Fig. 14. An internal cast of a small and very elongate pedicle-valve ; an nnusual variation in form. 



Schoharie grit. Albany county, N. Y. 

 Fig. 19. A pedicle-valve retaining the lirachidium in a silicihed and incrusted condition ; showing the 

 form of the cones and retaining in position the median septum of the brachial valve. 

 Corniferous limestone. IVillia^nsviUe, N. Y. 

 Fig. 20. A similar specimen, the spirals being unincrusted and exjiosed by weathering. 

 Fig. 21. The interior of an incomplete pedicle-valve ; showing dental plates and muscular impressions. 

 Fig. 22. The interior of a brachial valve ; showing the subtriangular, medially concave hinge-plate, dental 



sockets, median septum and elongate adductor muscular area. 

 Fig. 24. The hinge plate enlarged ; showing the median depiession, crural bases and supporting septum. 



X 3. 

 Fig. 25. Cardinal view of an internal cast of conjoined valves ; showing the impressions of the muscular 

 scars, teeth and dental lamell:e,'sookets and median sejilum. 

 Corniferous limestone. Western New York. 

 Fig. 26. An internal ca.st of the brachial valve. 



Schoharie grit. Schoharie, N. Y. 



Meristella lenta, Hall. 



Fig. 15. An internal cast of Ibe pedicle-vaUe ; shuwing the sliong muscular scars and the generally de- 

 pressed surface. X 2. 



Fig. 16. A preparation, showing the form of the spiral cones resting in the pedicle-valve, with the median 

 dorsal septum in position. 



Fig. 17. An internal cast of the brachial valve, showing its convexity and the position of the median sep- 

 tum. A portion of the tilling of the pedicle-cavity of the opposite valve is also exposed. X 2. 



Fig. 18. A longitudinal internal view, showing the position and form of the loop and one of the spiral 

 cones. Restored. 



Oriskany sandstone. Be Cewville, Ontariu. 



Meristella Barrisi, Hall. 



See Plate 43. 

 Figs. 27, 28. Two views of a preparation, showing the tbrm of one of the spiral cones. 

 Fig. 29. An internal cast of conjoined valves ; showing the jiosilion of the median septum and dental 



laraells. 

 Fig. 30. An internal cast of the pedicle-valve. 



Limestone of the Marcellus shale. Stafford, N. Y. 



Meristella Haskinsi, Hall. 



See Plate 43. 

 Fig. 31. The interior of a pedicle-valve retaining the deltidial plates, and showing the teeth and muscular 

 scars. 



Hamilton group. Canandaigua Lake, iV. Y. 



