126 



THE CHAIN OF LIFE. 



the Barramunda, which is thus the sole survivor, perhaps itself 

 verging on extinction, of a group of herbivorous fishes introduced, 

 it may be, contemporaneously with the first streams affording 

 the requisite vegetable food, and which have continued almost 

 without improvement or deterioration to the present time. 



Fig. ho.— Dental plate of Conchodus pUcatus (Dn.). Coal-formation of Nova Scotia. 



Acadian Geology, 



These fishes are, however, very closely connected with the 

 Ganoids, and there are some of these, with fringed fins and 

 overlapping scales, which, while regarded as true Ganoids, 

 resemble the Dipnoi v^ry closely. 







Fk;. ii:. — Dental plate of Ceraiodus Barrandii. Coal-formation of Bohemia. 



After Fritsch. 



Again, certain huge fishes, whose remains are found in the 

 Devonian of Ohio,^ had jaws on the same plan with those of 

 Lepidosiren, but of enormous size and strength (Figs. 113, 114, 

 ^ Dinkhthys Terrelli and D, Hertzeri (Newberry). 



