LIST OF ILLUSTRATIONS. 



Frontispiece. 



FIG. 1 — A. Common Roacli ; B. An Outline figure 

 of the Burbot {Lota vulgaris) 

 2 — Diagrammatic figure of an Eel 

 3 — Head of a young Polypterus . 

 4— The Evolution of Teeth and Scales 

 5— Skull of Dog-fish . 

 6— The Evolution of the Fish's Tail 

 7 — The Evolution of Fins . 

 8 — Head of GTiathonemus elephas 

 9 — Chiasmodon niger . 

 10 — Sticklebacks and Nest , 

 11 — A Larval Dog-fish . 

 12 — Fish Metamorphoses (three stages in the 



life history of the Eel) 

 13 — Three stages in the development 



Sword-fish .... 

 14 — Outline figure of the American Mud-fish 

 15 — Restoration of a Primitive Sturgeon 

 16 — Three extinct Ancestral Forms of Fishes 



17 — Three Primitive Sharks 



8 



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