Shark and Company 



Successive types of prehistoric Elasmobranch fishes are shown in this series. ( A ) Clad- 

 oselache, of the Devonian Period, with fins supported by simple parallel rods of 

 cartilage and the paired fins serving merely as balancers. (B) Fleur acanthus, typical 

 of the Permo-Carboniferous, with paired fins used as paddles. (C) Hybodus, of the 

 Jurassic, with paired fins for swimming, a persistent notochord and simple vertebral 

 arches. (D) Chlamydoselache, which exemphfies the Cretaceous and Tertiary types, 

 but which is still in existence today as the Frilled shark. 



Courtesy, American Museum of Natural History 



