PLATE XXXV. 



Zone of Aegoceras Henleyi. 



Fig. 1. Aegoceras acuticostatum, Wright. Lateral view, natural size. Woodwardian 



Museum, Cambridge. 

 — — Front view, natural size, showing the 



Inflexion of the ventral ribs. 



3. — — Siphonal area of the same shell. 



4. heterogenum, Young and Bird. Lateral view, natural size. Wood- 



wardian Museum Leckenby 

 collection. 



5. — — — Front view of the same shell. 



6. — — — Siphonal area of the same shell, 



showing the sudden enlarge- 

 ment of the whorl at the com- 

 mencement of the transforma- 

 tion scene. Natural size. 



7. — acuticostatum, Wright. Lobe-line, showing simple ramifications. 



