PLATE LXXy. 



Orthogeras Zeus. 



Pago 235. 



Fig. 1. An individual showing eight chambera, and a large portion of the chamber of habitation, with a 

 broad, shallow constriction near the aperture. Helderherg mountains, N. T. 



Fig. 2. Longitudinal section of another specimen, showing the depth of the chambeiB 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, fig. 1, showing the size and position of the siphuncle. 



Fig. 4. A septum of Ctbtocebis, showing position and size of siphuncle. See plate 95. 





