PLATE VII. 



Fig. 



1 — 3. Ammonites complanatus. 



1 . From the Grey Chalk of Harasey ; in the British Museum, from the col- 



lection of Dr. Man tell ; the original specimen figured, t. 569, of the 

 ' Mineral Conchology,' reduced to half its diameter. 



Iff. Side view. 

 1 b. Front view. 



2. A young specimen of the natural size ; in the British Museum, from the 



collection of Dr. Mantell. 



3. Outline of the margin of a septum, copied from pi. xcv of the 'Paleont. 



Franfaise Terrains Cretacees.' 



dl. The dorsal lobe. 

 sll. The superior lateral lobe. 

 i 1 1. The inferior lateral lobe. 

 a a a. Auxiliary lobes. 

 s d. The dorsal saddle. 

 Is. The lateral saddle. 

 t. The position of the siphuncle on the middle of the back. 



4. Ammonites obtectus ; from the Chalk with siliceous grains of Chardstock, in the 

 collection of Mr. Wiest. 



4a. Side view. 

 43. Front view. 



4c. Portion of the outline of a septum, only extending to the 

 lateral saddle. 



5 — 9. Ammonites falcatus. 



5. From the Grey Chalk of the Clayton Tunnel, on the Brighton Railway, in 



the collection of Mr. Catt. 

 6a and b. IVom the Chloritic Marl of Gore CUfF, Isle of Wight, in the 



collection of Mr. Saxby. 

 la and b. A specimen in the collection of Mr. Morris, from the Chalk with 



siliceous grains of Chaldon. 

 8a and b. From the Chloritic Marl of Bonchurch, Isle of Wight ; in the 



collection of Mr. Saxby. 

 9. Outline of a septum of a young specimen. 



