PLATE LXIY. 
Orthoceras Zeus. 
Page 235. 
Fig. 1. An individual showing eight chambers, and a large portion of the chamber of -habitation, with a 
broad, shallow constriction near the aperture. Helderberg mountains, N. Y. 
Fig. 2. Longitudinal section of another specimen, showing the depth of the chambers and the concavity of 
the septa. The position of the siphuncle is indicated by slight indentures in the septa. 
Fig. 3. A septum from specimen, tig. 1, showing the size and position of the siphuncle. 
Fig. 4. A septum of Cyrtoceras, showing position and size of siphuncle. See plate 95. 
