EXPLANATION OF PLATE XV. 



Fio. 



37 Bei.emnites irregularis. Characteristic specimens in the Bristol Museum. 



(From Frocester Hill.) 

 V. Ventral aspect. 

 /. Lateral aspect. 

 d. Dorsal aspect. 



s. Transverse section of the alveolar region. 



a. The apex urabilicated and striated [g, the mesial groove). 



38 «. Belemnites regularis, n. s. (From the Upper Lias, near Banbury.) (Short 

 variety.) 



/. Lateral aspect. 



V. Ventral aspect. 



-v'. Section across the alveolar cavity. 



a. The apex umbilicate and trisulcate. 



38 3. Longer variety of the same. 



/. Lateral aspect. 

 V. Ventral aspect. 

 s. Section across the alveolar cavity. 



39. Belemnites irregularis. (From Frocester Hill. ) 

 /. Lateral aspect, 



V. Ventral aspect of a larger variety. 

 s.' Section across the alveolar cavity. 



