PLATE LXIII. 



Zone of Harpoceras serpentinnm. 



Fig. 1. Harpoceras elegans, Sowerby. Side view, natural size. My collec- 

 tion. 



2. Front view of same, do. do. 



3. — — Back view do. do. do. 



4. ovatum, Young and Bird. Side view do. do. do. 



5. — — — Front view of same, do. do. 



6. — Back view do. do. 



7. — — Lobe-line, magnified. 



