PLATE LXVIII—Continued. 
CONOCARDIUM DENTICULATUM. 
Page 413. 
Pig’s. 24, 25. Left side and ventral views of an imperfect specimen, enlarged to three diameters. Fig. 25 
represents the denticulations of the margins as too slender, and interlocking more than in the 
specimen. 
Hamilton group. York, iV. Y. 
CONOCARDIUM CONCINNUM. 
Page 414. 
Pig. 26. Posterior view of a specimen. 
Hamilton group. Pratt’s falls, N. Y. 
Fig. 27. Ventral view of another individual. 
CONOCARDIUM LIRATUM. 
Page 414. 
Fig. 28. A right valve as obtained from a gutta-percha impression of a natural mould, enlarged to three 
diameters. 
Lower Chemung group. Ithaca,, JS. Y. 
Fig. 29. Anterior view of a specimen enlarged to three diameters. 
Lower Chemung group. Ithaca, N. Y. 
CONOCARDIUM TEGULUM. 
Page 415. 
Fig. 30. A fragment of an individual of this species. 
Fig. 31. An enlargement of the surface of the preceding. 
Niagara group. 
CONOCARDIUM INCEPTUM. 
Page 415. 
Fig. 32. Ventral view of a specimen, enlarged to two diameters. 
Lower Helderberg group. Albany Co., N. Y. 
CONOCARDIUM RELIQUUM. 
Page 415. 
Fig. 33. A view of the posterior end of a specimen as obtained from a gutta-percha impression. 
Chemung group. 
