PLATE XVI. 



(Figures 1-16, 18-22, 24-30, 34-44 by K. I'. WiiitfikM) ; 17, ;il by F. H Mkkic ; 23 copy.) 



Le'jenil. 



Fi" 



Fig. 



Fig. 

 Fig. 



D. Delti<iium, peiiic.le-valve. 

 C. Deltidium, brachial valve. 

 St. Cardinal tubes. 

 t. Teeth. 



b. Dental sockets. 

 8. Septum. 



j. Canlinal procesis. 



a. Anterior adductors, 

 a'. Posterior adductors. 



r. Anterior diductors. 

 r'. Posterior diductora. 



V. Brachial ridges. 



Genus CHONETES, Fischek dk Waldheim. 



(See Plate XVu.) 

 Page 303. 



Chonetes corxuta, 



Hall. 



1. A view of the pedicle-valve. X 2. 



Clinton group. SotUis Bay, N. Y. 



Chonetes setigeka. ll.ill. 



2. A view of the pedicle-valve. X 2. 



Waverly gi-oup. Penfield, Ohio. 

 5. Pedicle-valve of a larger siieciiuen with finer stris. X 2. 

 19. An enlargement of the surface striffi of this specimen. 

 Marcellus shales. Near Caledonia, N. T. 



Chonetes scitula, Hall. 



(?)Fig. 3. A pedicle-valve, with somewhat moi-e cii-cular outline and longei- car<linal spines than usual. X 2. 



Fig. 4. A view of the brachial valve ; showing the cai-dinal area and deltidium. 



Fig. 27. The interior of a brachial valve ; showing the structure of the cardinal process and the taint 



brachial ridges. X 2. 

 Fig. 32. The interior of the pedicle-valve ; showing the cardinal area and teeth. X 2. 



Hamilton group. Canandaigua Lake. N. Y. 

 Fig. 40. An enlargement of the cardinal portion of the valves; showing the hollow .spines and the curving 

 course of the spine-tubes through the substance of the cardinal area of the jiedicle-valve. X 8. 

 Hamilton gi'oup. Western New York. 

 Fig. 44. An internal ca.st of the pedicle-valve, retaining thi; tilling of the spine-tubes and showing their 

 convergence toward the beak before reaching the upper niai-gin of the area. X 8. 

 Chemung group. Cattaraugus county, N. Y. 



Chonetes mucronata. Hall. 



Fig. 6. A pedicle-valve with very coarse plications and apparently destitute of spines. X 2. 

 Fig. 7. A pedicle- valve with long, extremely divei-gent spines. X 2. 

 Marcellus shales. West Avon, N. Y. 



Chonetes acutiradiata, Hall. 



Fig. 8. The pedicle-valve. 



Corniferous limestone. fVilliamsvUle, N. Y. 



Chonetes Logaxi, Noiwood and Pratteii, vav. Aukoi;a. Hall. 



Fig. 9. Pedicle-valve, enlarged to show the fine concentric striae. X 3. 

 Fig. 18. An enlargement of the surface. 



Tnlly limestone. TidJy. N. Y. 



