LIST OF ILLUSTRATIONS. 



PAGE 



1. The " Lancelet," Rranchiosloma lanceolatum (recent) 1 



2. The " Hag-fish," Myxine australis (recent) ..... 1 



3. Mouth of " Lamprey," Petromyzon fluviatilis (recent) . . . 1 



4. " Conodonts," from the Cambrian, ten times natural size ... 2 



5. " Diphycercal," or primitive form of tail ..... 3 



6. " Heterocercal," or ancient form of tail ...... 3 



7. " Homocercal," or modern form of tail ...... 3 



8. Dermal tubercles of Plagiostomous Fishes ..... 4 



9. The " Port- Jackson Shark," Cestracion Philippi, Australia . . 4 



10. The Ray {Raja Murray i, Giinther), from Kergeulen's Island . . 5 



11. Spines of Plagiostomous and Chinircroid Fishes .... 5 



12. Portion of Spine of Edestes vorax, Coal-measures, Indiana, U.S.A. . 6 



13. Spine of Gyracanthus formosns, Coal-measures, Scotland ... 6 



14. Tooth of Lamna elegans, London Clay ...... 7 



15. Tooth of Carcharodon megalodon, Suffolk Crag .... 7 



16. Teeth of JVotidanus gigas, Red Crag, Suffolk ..... 7 



17. Skull of Notidanus (recent) ........ 8 



18. Spine of Lepracanthus Colei, Coal-measures, Ruabon ... 9 



19. Teeth of Acrodus Anningia, Lower Lias, Lyme Regis ... 9 



20. Dorsal spine of Hybodus, Lias, Lyme Regis ..... 9 



21. Jaw of " Port-Jackson Shark," Cestracion Philippi (recent) . . 10 



22. Side view of Jaws of " Port-Jackson Shark," Cestracion Philippi (recent) 10 



23. Jaw of Strophodus medius, Great Oolite, Caen, Normandy . .11 



24. Teeth of Cochliodus contortus, Carboniferous Limestone, Armagh . 11 



25. Squatina alifera (after Fraas), Lithographic Stone (Upper Oolite), Bavaria 12 



26. Squatina speciosa, Lithographic Stone (Upper Oolite), Bavaria . .12 



27. Some of the Central Teeth of Janassa linguaiformis, posterior aspect, 



Coal-measures, Northumberland ...... 



28. Jaws of Male and Female Skate, Raja clavata (recent) 



29. Dermal spines of the Thornback Skate, Raja clavata (recent) 



30. Lower Jaw of Edaphodon leptognathus, Middle Eocene, Bracklesham Bay 



31. Eiplacanthus striatus, Old Red Sandstone, Cromarty 



32. Acanthodes (restored figure after Kner and Roemer), Permian 



33. Dorsal surface of Pterichthys JTilleri (after Pander), O. R. S. Scotland 



34. Pterichthys cornutus, Agassiz, Old Red Sandstone, Scotland 



35. Coccostens (side view), Old Red Sandstone ..... 



36. Coccostens decipiens (dorsal aspect), Old Red Sandstone 



37. Jaws of Binichthys, Devonian, North America .... 



38. Pteraspis (restored), side view (after Lankester), O. R. S., Herefordshire 



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