PLATE LXXV. 



SCHIZODUS TUMIUUS. 



Page US. 

 Figs. 1, 2. The right side and cardinal view of a cast of the interior, showing muscular scars and pallial line. 

 Comiferous limestone. Columbus, Ohio. 



SCHIZODUS APPRESSUS. 

 Page 449. 

 Fig. 3. A cast of an interior of a right valve, showing umbonal fun-ows, muscular scai-s and pallial line. 



Hamilton group. Pratt's falls, Onondaga Co., N. Y. 

 Fig. 4. A left valve of ordinary foi-m. 



Fig. 5. A specimen preserving both valves conjoined by the ligament. 

 Fig. 6. A left valve which is somewhat iiasute at post-inferior extremity. 



Hamilton group. Shore of Cayuga lake, N. Y. 

 Fig. 7. A right valve of elongate form. 



Hamilton group. Shore of Cayuga lake, N. Y. 

 Fig. 8. A small right valve of rotund form. 



Hamilton group. Schoharie Co., N. Y. 

 Fig. 9. A larger right valve. 



CyTHEROTX)N NASUTUS. 

 Page 511. 

 See Plate 95. 

 Fig. 10. The left siile of the specimen described. See plate 95 for a coi'rect drawing of this specimen. 



Hamilton group. Hardy Co., Va. 

 Fig. 11. Cardinal view of the preceding, showing the inipi-cssions of the cardinal teeth. 

 Pig. 12. The interior of the canlinal portion of the same, as obtained from a gutta-pei-cha impression. 



SCHIZODUS ELLIPTIOUS. 



Page 450. 

 Fig. 13. A right valve. 



Hamilton group. Shore of Canandaigua lake, N. Y. 



Yigs. 14, 15. Two small left valves. 



Hamilton group. Shore of CaiuiTulnigna lake, N. Y. 



'^^KSiu.. 



SCHIZODUS GKEGARIUS. 

 Page 452. 



See Plate 95. 

 Pig. 16. A left valve of this species. 



Chemung group. Near T%oga, Pa. 

 Pig. 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 RHOMBBUS. 



Page 452. 

 Fig. 19. A left valve. 



Chemung gi-oup. Hobbieoille, N. Y. 

 Pig. 20. A left valve of somewhat different foi-m. 



Chemung group. Chautauqua Co., N. Y. 'HtSl^k 



Figs. 21-23. A left valve and two right valves of this species. '^^^ 



Chemung group. Cattaraugus Co., N. Y. 



