PLATE LXXV. 
SCHIZODUS TUMIDUS. 
Page 44S. 
Figs. 1, 2. The right side and cardinal view of a cast of the interior, showing muscular scars and pallial line. 
Corniferous limestone. Columbus, Ohio. 
Fig. 3. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. 
Fig. 8. 
Fig. 9. 
Fig. 10. 
Fig. 11. 
Fig. 12. 
Fig. 13. 
Figs. 14, 
SCHIZODUS APPRESSUS. 
Page 449. 
A cast of an interior of a right valve, showing umbonal furrows, muscular scars and pallial line. 
Hamilton group. Pratt’s falls, Onondaga Co., N. Y. 
A left valve of ordinary form. 
A specimen preserving both valves conjoined by the ligament. 
A left valve which is somewhat nasute at post-inferior extremity. 
Hamilton group, Shore of Cayuga lake, N. Y. 
A right valve of elongate form. 
Hamilton group. Shore of Cayuga lake, N. Y. 
A small right valve of rotund form. 
Hamilton group. Schoharie Co., N. Y. 
A larger right valve. 
Cytherodon nasutus. 
Page 511. 
See Plate 95. 
The left side of the specimen described. See plate 95 for a correct drawing of this specimen. 
Hamilton group. Hardy Co., Va. 
Cardinal view of the preceding, showing the impressions of the cardinal teeth. 
The interior of the cardinal portion of the same, as obtained from a gutta-percha impression. 
SCHIZODUS ELLIPTICUS. 
A light valve. 
Hamilton group. 
15. Two small left valves. 
Hamilton group. 
Page 450. 
Shore of Canandaigua lake, N. Y. 
Shore of Canandaigua lake, N. Y. 
SciIIZODUS GREGARIUS. 
Page 452. 
See Plate 95. 
Fig. 16. A left valve of this species. 
Chemung group. Near Tioga, Pa. 
Fig. 17. A portion of a block preserving the remains of several individuals. 
Chemung group. Near Tioga, Pa. 
Fig. 18. A right valve. 
Chemung group. Near Tioga, Pa. 
SCHIZODUS RHOMBEUS. 
Page 452. 
Fig. 19. A left valve. 
Chemung group. Hobbieville, N. Y. 
Fig. 20. A left valve of somewhat different form. 
Chemung group. Chautauqua Co., N. Y. 
Figs. 21-23. A left valve and two right valves of this species. 
Chemung- group. Cattaraugus Co., N. Y. 
