PLATE XLVIII. 
PALA20NEILO constricta. 
Page 333. 
See Plate 51. 
Figs. 1-3. Three right valves of somewhat different proportions. 
Hamilton group. Central New York. 
Figs. 4, 5. Two right valves. 
Fig. 6. Cardinal view of a cast of the interior. 
Fig. 7. An enlargement of a specimen retaining the valves in conjunction. 
Hamilton group. Bellona, Yates Co., N. Y. 
Fig. 8. A left valve enlarged showing the crenulations of the hinge-line. 
Hamilton group Shore of Cayuga lake, N. Y. 
Fig. 9. A cast of a left valve, enlarged to two diameters. 
Hamilton group. Near Cumberland, Md. 
Fig. 10. A gutta-percha impression from the preceding, showing the character of the interior, enlarged. 
Fig. 11. An enlargement of the surface from the specimen fig. 8. 
Fig. 12. A cast of the interior of a left valve showing muscular impressions and crenulated hinge, enlarged. 
Hamilton group. Fultonham, Schoharie Co., N. Y. 
Fig. 13. A partial cast of a right valve showing the crenulations of the hinge, and preserving the shell and 
markings along the pallial line, enlarged. 
Hamilton group. Bears gulf, Schoharie Co., N. Y. 
Fig. 14. A cast of two valves in conjunction showing the muscular scars and hinge crenulations, enlarged. 
Hamilton group. Near Cumberland, Md. 
Fig - . 15. An enlargement of the hinge from the specimen fig. 9. 
Fig. 16. A cast of a small individual, somewhat more nasute at the posterior extremity than usual. 
Lower Chemung group. Near Ithaca, N. Y. 
