LIST OF ILLUSTRATIONS IN TEXT. 
IX 
FIG. PAGE 
49. Dorsal shield of Cyathaspis banksi , from the Downtonian of 
Herefordshire. (After Lankester) ..... 56 
50. Restoration of Pteraspis rostrata, from the Lower Old Red 
Sandstone of Herefordshire. (After A. S. Woodward) . 56 
51. Dorsal shield of Pteraspis rostrata. (After Lankester) . 56 
52. Restoration of Drepanaspis gemuendenensis, from the Lower 
Devonian of Germany. (After R. H. Traquair) . . 57 
53. Restoration of Cephalaspis murchisoni, from the Downtonian 
of Herefordshire. (After A. S. Woodward) ... 58 
54. Restoration of Pterichthys milleri, from the Middle Old Red 
Sandstone of Scotland. (After R. H. Traquair) . . 59 
55. Restoration of Palceospondylus gunni, from the Middle Old 
Red Sandstone of Caithness. (After R. H. Traquair) . 60 
56. Conodonts from the Cambrian. (After G. J. Hinde) . . 60 
57. Protocercal or diphycercal tail ...... 61 
58. Heterocercal tail ....... 61 
59. Homocercal tail ........ 61 
60. Restoration of Acanthodes wardi, from the British Coal 
Measures . . . . . . . .63 
61. Fin-spine of Gyracanthus formosus, from the British Coal 
Measures ......... 64 
62. Spiral row of teeth of Helicoprion bessonowi, from the Permo- 
Carboniferous of Russia. (After A. Karpinsky) . . 65 
63. Restored skeleton of Pleuracanthus decheni, from the Lower 
Permian of Bohemia. (After A. Fritsch) ... 66 
64. Jaw with teeth of Cochliodus contortus, from the Carbon¬ 
iferous Limestone of Armagh ..... 67 
65. Tooth of Notidanus gig as, from the Red Crag of Suffolk . 68 
66. The Port Jackson Shark (Gestracion philippi ), from 
Australia ......... 69 
67. Jaw of the Port Jackson Shark (Gestracion philippi ), from 
Australia ......... 69 
68. Dorsal fin-spine of Hybodus, from the Wealden of Sussex . 70 
69. Teeth of Acrodus arming ice, from the Lower Lias of Lyme 
Regis .......... 70 
70. Jaw of Asteracanthus (Strophodus medius), from the Great 
Oolite of Normandy. (After Owen) . . . .71 
71. Tooth of Odontaspis elegans, from the London Clay of 
Sheppey ......... 71 
72. Crown of tooth of Carcharodon megalodon, dredged from 
the deep sea by the “ Challenger ”. . . . .72 
73. Rhinobatus bugesiacus, from the Lithographic Stone of 
Bavaria. (After Zittel) . . . . . .73 
74. Mandible of Ptychodus decurrens , from the English Chalk. 
(After A. S. Woodward) ...... 74 
75. Skin-tubercle of the existing Thornback, Raja ... 74 
76. Mandibular tooth of Edaphodon leptognathus, from the 
Bracklesham Beds, Sussex . . . . . .75 
77. Restoration of Dipterus valenciennesi, from the Middle Old 
Red Sandstone of Scotland. (After R. H. Traquair) . 77 
78. Teeth of Palaeozoic Dipnoi ...... 77 
79. The Australian Mud-fish, Geratodus forsteri, from Queens¬ 
land .......... 
78 
