PLATE L XXXV.—Continued. 
Qrthoceras emaceuatum. 
Page 292. 
See Plate 39. 
Fig. 16. A septate fragment, showing the depth of the chambers. The specimen is broken and flattened 
from compression. Hamilton group. Jaycox Run, Genesee county, N. T. 
Cyrtoceras DENSTJM. 
Page 363. 
Fig. 17. A chambered fragment, showing the apical angle of the tube and the regular depth of the air- 
chambers, with the straight and horizontal septal sutures. Hamilton group. Cumberland, Md. 
Fig. IS. Septum of the preceding, showing the size and position of the siphuncle, the areola around its inser¬ 
tion in the septa, and the transverse section of the tube. 
Fig. 19. A longitudinal section of a fragment, showing the elements of the siphuncle, the concavity of the 
septa, and a slight exogastric curvature of the tube. Hamilton group. Cumberland, Md. 
