PLATE III. 
Aviculopecten Idas. 
Page 13. 
See Plate 24. 
Fig. 1. A small right valve. 
Hamilton group. Fultonham, Schoharie Co., N. Y. 
Fig. 2. A larger example of more nearly normal proportions. 
Hamilton group. Darien, N. Y. 
Aviculopecten scabridus. 
Page 7. 
Fig. 3. A young individual, apparently, of this species, slightly narrowed by compression. 
Hamilton group. Bellona, iV. Y. 
Fig. 4. A left valve with the surface much distorted, but preserving a very perfect outline. 
Hamilton group. Canandaigua lake, N. Y. 
Fig. 5. The cardinal portion of a rig-ht valve. 
Hamilton group. Schoharie Co., N. Y. 
Fig. 6. A left valve of medium size ; imperfect at the cardinal extremities. 
Hamilton group. Delphi Falls, N. Y. 
Fig. 7. An imperfect right valve preserving the surface characters of the ears, as obtained from the 
matrix after the removal of the specimen. 
Fig. 8. An enlargement from the surface of a specimen preserving the test. 
Hamilton group. Geneseo, Livingston Co., N.- Y. 
Fig. 9. An enlargement of the surface of specimen, fig. 7, taken from the middle of the valve. 
Fig. 10. A large left valve preserving a very perfect outline, with a portion of the test adhering to the lower 
anterior portion. 
Hamilton group. Bellona, N. Y. 
Fig. 11. An enlargement of a portion of the test of the preceding specimen. 
Fig. 12. An enlargement from the surface of a specimen denuded of the test. 
. Hamilton group. Crooked lake outlet, N. Y. 
