FISHES OF THE DEVONIAN AGE. 63 
teeth are excavated below and were apparently set upon a cartilaginous jaw, 
as in Lhynchodus and Chimera; they are usually of the shape of a shoe, 
from one to five inches long, the place of the opening in a shoe filled with 
an enameled, transversely ridged, triturating surface. In some teeth this 
enamel portion is raised, in others depressed, as though one fitted into the 
other. The motion of the jaws must have been forward and back, and the 
grinding apparatus is as complete as that possessed by the elephant. None 
of the teeth of Ptyctodus seem to have been found in Germany, England, or 
the eastern United States; but in the Devonian rocks of Russia, Iowa, and 
Illinois they are quite numerous. 
The Devonian fishes of Canada have been already alluded to. Many 
years ago spines of Machwracanthus sulcatus were sent to me for examina- 
tion by Sir William Dawson, and I have since received them from several 
localities. 
From the Devonian rocks of Gaspé a species of Cephalaspis was ob- 
tained some years since by Sir William Dawson, and was named by Mr. 
Ray Lankester C. Dawsoni. 
In 1880 Mr. A. H. Foord, of the Geological Survey of Canada, col- 
lected from the Devonian rocks on the shore of Scaumenae Bay, Province 
of Quebec, a large number of very interesting fossil fishes, which were sub- 
sequently described by Mr. J. F. Whiteaves.!. These include Pterichthys, 
Diplacanthus, Phaneropleuron, Glyptolepis (two species), Cheirolepis, and a 
new genus described by Mr. Whiteaves under the name of Lusthenopteron, 
so named from its strong ‘fin rays. 
Previous to this discovery no species of Pterichthys, Cheirolepis, Phane- 
ropleuron or Glyptolepis had been found in North America, and in an earlier 
review” of the fossil fishes of this country I noted ‘the absence from all 
our collections of many of the most abundant and best-known genera of 
the Scotch and English Old Red Sandstone fishes.” On the other hand, I 
called attention to the fact that up to that time (1873) all the most impor- 
tant ichthyolites of our American Devonian were unknown in Europe; ac- 
counting for the difference between the Devonian fishes on opposite sides of 
the Atlantic by saying that our fishes were mostly obtained from the Cor- 
‘Canadian Naturalist, vol. 10, p. 93. *Palxontology of Ohio, vol. 1, p. 273. 
