182 PALEOZOIC FISHES OF NORTH AMERICA. 
of an immense lapse of time at an age of the world when fishes had become 
numerous and diyersified, it is not surprising that they have left here a 
voluminous record. Though Amphibians had already made their appear- 
ance, as we learn by the foot-prints on Lower Carboniferous rocks, fishes 
were still the ruling dynasty of the animal kingdom, and had not yet en- 
countered the rivalry of the powerful aquatic reptiles of the Reptilian age, 
or the mammals of the Tertiary. In the Devonian they had the ocean, 
lakes, and rivers all to themselves, and with abundant food and no formida- 
ble enemies, they multiplied rapidly and soon had taken complete posses- 
sion of the world of waters. In the Carboniferous age they had been modi- 
fied and specialized until some of them were adapted to all its conditions, 
and had taught themselves to capture and digest all kinds of food that the 
seas contained. 
Almost daily additions are made to the list of fishes found in the Car- 
boniferous limestone, and it is evident that we have much yet to learn of 
its fish fauna, but already the names of the species described from this 
formation compose a longer catalogue than that of any other geologic sys- 
tem, perhaps indeed of all others. When we combine the contributions 
to its ichthyology made by Agassiz, Portlock, De Koninck, Von Beneden, 
Egerton, McCoy, Davis, Worthen, St. John, and the writer, we shall find 
that they embrace nearly one-half the literature of fossil fishes. In the 
Monograph of the “Fossil Fishes of the Carboniferous Limestone Series of 
Great Britain,” by Mr. James W. Davis,’ one hundred and _sixty-three 
species are enumerated, while in volumes 2, 4, 6, and 7 of the Hlinois Geolog- 
ical Survey three hundred and ninety-one species of fishes are described by 
Mr. St. John and myself, of which three hundred and thirty-three are from 
the Carboniferous limestone and Kinderhook group. To these should be 
added the species described by Dawson,” Leidy,* and the writer,* and we 
have an aggregate of nearly four hundred species from the Carboniferous 
limestone of this continent, and about six hundred species from this country 
and Europe. Of these nearly all are Elasmobranchs, and the descriptions 
1 Scientific Trans. Royal Dublin Soc., 2d series, vol. 1. 
? Acadian Geology. 
3 Jour. Acad. Nat. Sci., Phila. 
*Rep. Geol. Survey Indiana for 1878, 
