170 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



back as far as the Silurian. The Lamias or Lamnidce, 

 with long triangular teeth, have appeared since the 

 Carboniferous epoch. The genus Squatina or Sea- 

 Angel has representatives very near to the present 

 type, in the lithographic limestone of Bavaria, 

 and, perhaps, in the Permian of Thuringia. The 

 group of existing Chimceras, with the mandible com- 

 pletely welded to the cranium, dates at least from 

 the Jurassic, and even, according to Newberry, from 

 the Devonian. The sensational discovery of the 

 Dipneuston named Barramundi, in the rivers of 

 Queensland, which was recognized to be identical in 

 kind with the Ceratodus of the Trias, is still in the 

 minds of all naturalists. The Polyp tera of the Nile 

 is, no doubt, the little modified descendant of the 

 rhomb-scaled Ganoids, such as the Osteolepis of the 

 Devonian red sandstone. The two branches of 

 the existing American Ganoids, Lepidosteus and 

 Amia, go back at least to the lower Eocene. The 

 type of our pike or Esocidse already exists with few 

 modifications in the upper Cretacea of New Jersey ; 

 the genus herring or Clupra in the Neocomian of the 

 Voirons. The salmon has for precursors the Os- 

 meroidse of the English Chalk ; the genus Beryx 

 goes back to the higher Cretacean. The anurous 

 Amphibians of the Toad group are now known even 

 in the upper Jurassic. The swimming marine 

 Reptiles of the Ichthyosaurus and Plesiosaurus 

 types have evolved into numerous branches in 

 the Secondary seas from the Trias till the end of 

 the Cretacean, and we may expect to some day 

 discover their precursors in Primary strata. The 

 highly specialized group of the Chelonians is already 



