OF CREATION. 99 



singular and robust proportions. Although the head 

 is small, the naked jaws (covered with enamel in- 

 stead of skin) are lined with a double row of for- 

 midable teeth, the outer ones being thickly set and 

 fringing the enamelled edges of the mouth, but the 

 inner ones wider apart, and at least twenty times the 

 size of the others. The scales on the body of this 

 fish, and the bones, are so like what is seen in rep- 

 tiles, that they were, when first discovered, supposed 

 to belong to some large saurian ; and the scales might 

 indeed have served for the defensive armour of a 

 crocodile five times as large as the fish. Not less than 

 five species of this remarkable genus have been already 

 determined from the beds of the old red sandstone 

 period, and eight from the carboniferous rocks, all of 

 them exhibiting more or less distinctly the peculiarly 

 massive and robust character of the family. 



But the great reptilian fish were not the only in- 

 habitants of the sea during this period, nor were they 

 even the only ones of large size and possessed of 

 great strength and voracity. Not less than sixty 

 species belonging to various genera, all nearly al- 

 lied to the shark tribe and some of them of very 

 large proportions, are indicated by the remains of 

 teeth discovered in various localities in the lime- 

 stones, sandstones, and shales of the carboniferous 

 series ; and thirty-three species have been deter- 

 mined from fragments of fins and detached vertebrae 

 from the same beds. Now, as there are no more 

 than seven species of shark-like animals determined 

 from the fossils of the old red sandstone, even in- 

 cluding two which may be identical with some of the 

 other five, it seems that a great and important 



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