TUE DEVONIAN AGE. 90 



to these fishes, there were others, represented prin- 

 cipally by their strong bony spines, which must 

 have been allied to some of the families of modern 

 sharks, most of them, however, probably to that com- 

 paratively harmless tribe which, furnished with flat 

 teeth, prey upon shell-fishes. There are other fishes 

 difficult to place in our systems of classification ; and 

 among these an eminent example is the huge 

 Dinichthys of Newberry, from the Hamilton group of 

 Ohio. The head of this creature is more than three 

 feet long and eighteen inches broad, with the bones 

 extraordinarily strong and massive. In the upper 

 jaw, in addition to strong teeth, there were in front 

 two huge sabre -shaped tusks or incisors, each nearly a 

 foot long ; and corresponding to these in the massive 

 lower jaw were two closely joined conical tusks, fitting 

 between those of the upper jaw. No other fish 

 presents so frightful an apparatus for destruction ; and 

 if, as is probable, this was attached to a powerful 

 body, perhaps thirty feet in length, and capable of 

 rapid motion through the water, we cannot imagine 

 any creature so strong or so well armed as to cope 

 with the mighty Dinichthys. 



The difference between the fTshes of the Devonian 

 and those of the modern seas is well marked by the 

 fact that, while the ordinary bony fishes now amount 

 to probably 9,000 species, and the ganoid fishes to 

 less than thirty, the finny tribes of the Devonian are 

 predominantly ganoids, and none of the ordinary type 

 are known. To what is this related, with reference 



