PLATE XV. 



Fig. Page. 



1. Microdon radiatus, Agassiz ; skull, right side view, twice nat. size. — Middle Purbeck Beds ; 



Swanage, Dorset. British Museum, no. P. 7455. Jr., frontal ; A-., lower median keel 

 on parasphenoid ; me., mesethmoid ; ors., orbitosphenoid (?) ; pa., parietal; jms-* para- 

 sphenoid; r.s., ridge-scale fused with occiput; socc, supraocci])ital ; sq., squamosal; 

 vo., vomer. 59. 



2. Ditto ; caudal fin, twice nat. size. — Ibid. British Museum, no. 19013. 63. 



3. Ditto ; some abdominal flank-scales, left side, outer view, twice nat. size. — Ibid. Cunnington 



Collection (B. M. no. 46333). 64. 



4. Ditto ; some abdominal flank-scales, right side, inner view showing riblets, twice nat. size. — 



Ibid. British Museum, no. 44844. 64. 



5. 5 a. Ditto ; two abdominal flank-scales, right side, inner view, showing peg-and-socket 



articulation, twice nat. size. — Ibid. Dorset County Museum, Dorchester. 64. 



6. Ccelodus mantelli, Agassiz; portion of vomerine dentition, oral view and right side view (6 a), 



three-halves nat. size, with a median tooth enlarged three times (6 b), and a transverse 

 section of the dentition (6 c), three-halves nat. size. — Wealden ; Tilgate Forest, Sussex. 

 Mantell Collection (B. M. no. 28417). 66. 



7. Ditto ; right splenial, oral view, three-halves nat. size. — Wealden ; Hastings, Sussex. 



Enniskillen Collection (B. M. no. P. 3763). 67. 



8. Ditto ; portion of right splenial dentition, oral view, twice nat. size. — Wealden ; Tilgate 



Forest. Mantell Collection, no. 2709. 67. 



9. Ditto; portion of left splenial dentition, oral view, three times nat. size. — Ibid. Type 



specimen of Gyrodus mantelli, Agassiz. Mantell Collection (B. M. no. 28415 a). 67. 



10. Ditto ; left splenial, oral view, twice nat. size. — Ibid. Mantell Collection (B. M. no. 28415 b). 67. 



11. Ditto ; left splenial, oral view, and hinder view (11 a), twice nat. size. — Lower Wealden or 



Upper Purbeck Beds ; Netherfield, Sussex. Teilhard & Pelletier Collection (B. M. no. 



P. 11903). 67. 



12. Ccelodus midtidens, sp. nov.; right splenial, oral view, twice nat. size. — Wealden ; Sevenoaks, 



Kent. The type specimen. Museum of Practical Geology, London, no. 7492. 68. 



13. Ditto; portion of right splenial dentition, oral view, twice . nat. size. — Wealden; Battle, 



Sussex. Bowerbank Collection (B. M. no. 39215). 68. 



14. Coelodus hirudo (Agassiz) ; a principal tooth of the left splenial dentition, oral view, front 



view (14a), and end view (14 b), three-halves nat. size. — Wealden; Tilgate Forest, 

 Sussex. The type specimen. Mantell Collection, no. 2706. 68. 



15. Ditto ; a principal tooth probably of the vomerine dentition, oral view, hinder view (15 a), 



and lower view (15 b), three-halves nat. size. — Wealden ; Hastings, Sussex. Rufford 

 Collection (B. M. no. P. 9838). 68. 



16. Ditto; a principal tooth, oral view, twice nat. size. — Wealden (Wadhurst Clay) ; Hastings. 



Teilhard & Pelletier Collection (B. M. no. P. 11900). 69. 



17. Ditto; an imperfect lateral tooth, three times nat. size. — Ibid. Teilhard & Pelletier 



Collection (B. M. no. P. 11901). 69. 



18. Ditto ; lateral tooth, five times nat. size. — Ibid. Teilhard & Pelletier Collection (B. M. no. 



P. 11902). 69. 



19. Cadodus Ixvidens, sp. nov. ; right splenial, oral view, three-halves nat. size. — Middle 



Purbeck Beds ; Swanage, Dorset. The type specimen. British Museum, no. P. 10679. 69. 



20. Ditto ; left splenial, oral view, twice nat. size. — Ibid. British Museum, no. 33480. 69. 



