PLATE XXI. 



Parhinsoni-zone. 

 Figs. 1, 2. — (Ecotraustes rugosus, 8. Buchnan. 



Fig. 1. — Side view. The ribs on the inner area are scarcely coarse enough. 

 East Coker, near Yeovil, Somerset. My Collection. 



Fig. 2. — Front view of the same specimen. The inner margin is depicted too 

 abrupt; it should be subconvex. 



Concavum-beds. 

 Figs. 3 — 9. — Ludwigia Lucyi, S. Buchman. 



Fig. 3. — Side view of a specimen with no part of the body-chamber present. 

 Bradford Abbas, Dorset. My Collection. (Page 104.) 



Fig. 4. — Front view of the same specimen showing the strong carina. The 

 inner margin is concave. 



Fig. 5. — Side view of a smaller example. Bradford Abbas, Dorset. My 

 Collection. 



Fig. 6. — Front view of the same specimen, showing a peculiarly flattened 

 ventral area. 



Fig. 7. — Side view of a smaller example, showing the bifurcate, reflexed 

 ribs characteristic of the genus. Bradford Abbas, Dorset. My Collection. 



Fig. 8. — Side view of a young example. Bradford Abbas, Dorset. My 

 Collection. 



Fig. 9. — Front view of the same specimen, showing the inflated sides, and the 

 rounded ventral area destitute of keel. 



Figs. 10, 11. — Ludwigia Ldcyi, 8. Buchman, variety. 



Fig. 10. — Side view of a specimen without any carina. Probably from Half- 

 way House, near Sherborne, Dorset. Very kindly presented to me by Mr. W. C. 

 Lucy, F.G.S. (Page 105.) 



Fig. 11. — Front view of the same specimen, showing the almost complete 

 absence of the carina even where the test is present. 



