Fig. 



11. Bblemnitella QUADRATA ; froiu the Collection of Mr. Bowerbank. 



lla. Section, showing the conical form of the lower part of the alveolar 



opening, and the fissure. 

 11^. The same, enlarged. 



12, 13, 14, 15, and 16. Belemnitella plena; from the Grey Chalk, near Dorking. 

 12a. Dorsal view. 

 125. Upper end, with the lower part of the alveohis preserved. 



13. A young specimen. 



14. Section of a specimen, from which the alveolus is entirely broken off. 

 1 5<2. Dorsal view of a specimen, broken off at the apex of the alveolus. 

 155. Broken end of the last. 



16. Section of a young specimen. 



17. Bklemnites ultimus; from the Chloritic Marl of Bonchurch in the Isle of Wight, 

 in the Collection of Mr. Saxby. 



17(2. Side view. 



175. Ventral view. 



17c. Outline of the opening. 



