PLATE I. 



Fig. 

 1, 2, and 3. Belemnitella mucronata ; from the Upper Chalk, near Norwich. 



1. Ventral view, with the fissure. 



2a and d. Dorsal and lateral views of a specimen, in which the vascular 



impressions are well seen. 

 2c. Alveolus from above. 

 3. Section of another specimen, showing the eccentric position of the 



alveolus, and traces of the edges of the septa. 



4, 5, and 6. Belemnitella lanceolata ; from the Uppier Chalk, near Norwich. 



4(2, d, and c. Dorsal, lateral, and ventral views of one specimen. 

 4:d. Alveolus from above. 



5. Ventral view of a young specimen. 



6. Section of another specimen, showing the central alveolus. 



7. Belemnitella quadrata; from the Middle Chalk of Kent, in the collection of 



Mr. J. G. Lowe ; this specimen is broken at the top. 



7a. Dorsal view. 



7d. Side view, 



7c. Portion of the granulated surface, magnified. 



8. Belemnitella quadrata; from the Middle Chalk of Kent, in the collection of 



Mr. Bowerbank. 



8a. Dorsal view, showing the two lateral depressions. 



83. The alveolar opening slightly broken away at the edges. 



9. Belemnitella quadrata ; a young specimen from the Upper Chalk of Northfleet 



in the collection of Mr. Morris, with the two vascular impressions strongly 

 marked. 



9^. Dorsal view. 

 dd. Lateral view. 



10. Belemnitella quadrata; alveolar opening from above, perfectly preserved. In the 

 collection of Mr. Bowerbank. 



