PLATE XXXIX. 



Zone of Aegoceras Ibex. 



Fig. 1. Aegoceras Loscombi, Sowerby. Lateral view of a strongly ribbed specimen, 



natural size. 



2. — — — Siphonal area, showing prominent ribs do. 



3. — — — Another specimen of the same species. 



4. — Ibex, Quenstedt. Lateral view, magnified. 



5. — — — Another specimen with definite ribbing. 



6. densinodum, Quenstedt. Lateral view, natural size. 



7. — — — Front view of the same. 



8. — — — Lateral view of another specimen, with 



an additional row of tubercles. 



9. — Siphonal area of the same, showing ribs 



and spines. 

 10. — — Lobe-line of this species. The siphonal 



shorter than the principal lateral lobe, 

 which is split up into many divisions. 



All the specimens figured in this plate belong to my collection. 



