PLATE XXXVIII. 



Ammodiscus. 



Figures 1-3. — Ammodiscus incertus, d'Orbigny, sp., 



Fig. 1. a, Lateral aspect : b, peripheral aspect, 

 Fig. 2. Small specimen, 



Fig. 3. Test laid open horizontally, showing the spiral 

 cavity and the relative thickness of the wall, 



x 15 



,, 4-6. — Ammodiscus tenuis, Brady, . . • • 332 



Fig. 4. Small specimen, . . . x 25 



Figs. 5 a, 6. Large examples, lateral aspect ; 5 b, peri- 

 pheral aspect, . 



x 15 



„ 7-9. — Ammodiscus gordialis, Jones and Parker, sp., . x 70 333 



„ 10-16. — Ammodiscus charoides, Jones and Parker, sp., . x 70 334 



Fig. 16. Section of the test. 



„ 17-19.' — Ammodiscus shoneanus, Siddall, sp., . . x 100 335 



a, a, Lateral aspect ; b, b, oral aspect. 



„ 20-22. — Ammodiscus spectabilis, Brady, . . . x ] 2 336 



