PLATE XLV. 



Zone of Amaltheus oxynotus. 



Fig. 1. Amaltheus Guibalianus, d'Orbigny. Side view, young shell, natural size. 



My collection. 



2. — — Siphonal area of do. do. 



3. — — Front view of a larger fossil showing 



the shape of the aperture, nat. size. 



4. — — Side view of another example showing 



the lobes and saddles in situ. 



5. — — Lobe-line showing the lobes and 



saddles enlarged, from a tracing on 

 the fossil. 



6. — — — Front view of a larger specimen show- 



ing siphonal area, keel, and terminal 

 costae. 



7. — Side view of the same specimen 



showing the lateral foldings and 

 umbilicus, natural size. 



