PLATE XXII A. 
Zone of Amaltheus owynofus. 
Fig. 1. Arietites impendens, Young 8f Bird. Side view, natural size. Woodwardian 
Museum, Cambridge. 
2. — — — Front view of the same shell. 
3. — — — Siphonal area of do. do. 
4. — — — Young shell with sharp ribs and 
sulci. 
5. — — — The lobe-line magnified. 
6. — CoiAjmoiatu, d' Orhigny . Side view, natural size. Woodwardian 
Museum, Cambridge. 
7. — — — Front view of same shell. 
8. — — — Siphonal area of do. do. 
9. — — — The lobe-line, highly magnified. 
