PHYLOGENY 



Figure 54. A Page of Fishes. A, an ostracoderm, Hemicyclaspis; B, a lamprey, Ento- 

 sphenus; C, a placoderm, Dinichthys; D, a shark, Borborodes; E, a ray, Dasyatis; F, 

 a sturgeon, Scaphirht/nchiis; G, a garpike, Lepisostciis; II, the living crossopterygian, 

 Latimeria; I, a teleost, Chaenuhryttus. (A, C, and // redrawn from Romer. ) 



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