Fig. 

 1,2. 



5, 6, 7, 8, 9. 



10. 



11. 



12, 13. 

 14. 



PLATE XVIII. 



Ithynchonella inconstans. From the Kimmeridge Clay. In these two 



specimens the twist is differently disposed ; 

 fig. 1 is the largest example I have 

 examined. 



,, „ Another specimen from Kimmeridge Clay. 



,, • „ From the upper beds of the Inferior Oolite. 



,, tetraedra. Different varieties, with a variable number of 



plaits on the mesial fold; fig. 7 is the 

 largest example I have seen, and forms a 

 well-marked variety. 



„ ,, A most remarkable variation, approaching 



much to B. decorata, and said to be from 

 the Inferior Oolite of Cheltenham. 



„ sub-variabilis. A var., with only two plaits. Another specimen 



is figured in PI. XV, fig. 7. 



„ Morierei. Two specimens from the Cornbrash. 



Lingula ovalis, Sow., nat. size, from the Kimmeridge Clay. 



