FISHES OF THE DEVONIAN AGE. 2 
tile-sealed Ganoids, allied to Palaoniscus, were there, and served as food for 
the larger ones, as we learn from their scales and bones in coprolites, but no 
entire individuals have yet been found. 
In Canada a most interesting fish fauna has been discovered in the 
Upper Devonian rocks, and many genera and species have been described 
by Mr. Whiteaves, the paleontologist of the Canadian Geological Survey. 
These fishes are generally small, are closely allied to, and in some instances 
perhaps identical with, the fishes of the Upper Old Red Sandstone of Scot- 
land, and, like them, were apparently the inhabitants of fresh water. 
ORIGIN OF THE DEVONIAN FISHES. 
The derivation of this fish fauna is unknown to us. The Devonian 
Cephalaspidians, Cephalaspis, Acanthaspis and Acantholepis, have affinities 
with Pteraspis and Scaphaspis of the Upper Silurian and are perhaps their 
descendants, but the origin of the most striking and characteristic elements 
in this fauna—the gigantic Dinichthide and the scaled and plated Ganoids, 
Onychodus, Macropetalichthys, and Asterosteus, as also the great Pterichthid 
Aspidichthys, and the Elasmobranchs Rhynchodus and Macheracanthus, 
among the largest and most highly specialized of all fishes—will perhaps 
always remain a mystery. Most of these were inhabitants of the Corniferous 
sea, and came in from the great oceanic basins with the flood which at a 
certain time inundated parts of the North American continent and deposited 
upon them the sediments which we call the Lower and Middle Devonian 
rocks. Presenting, as these fishes do, extreme forms of development in dif- 
ferent directions, they must have had a long term of existence previous to 
their appearance in the Devonian sea, but up to the present time we have 
discovered no evidences of their derivation from other invertebrate or verte- 
brate organisms, and no traces of the training schools in which they were 
brought to such diversified perfection according to their different plans of 
structure. 
STRATIGRAPHICAL DISTRIBUTION OF DEVONIAN FISHES. 
Neither in New York nor farther south has the Oriskany sandstone yet 
furnished any remains of fishes, but it is to be expected that when sought 
for patiently and discriminatingly they will be discovered. In Canada, 
