Prof. E. W. Claypole—Upper Devonian Fishes of Ohio. 447 
seems to have no analogy with the flattening of the body that is 
characteristic of the skates and rays. 
So far as it is possible to determine from the specimens thus far 
found, no spines were present anywhere on the fish. On this point 
the position of the fossils leaves little room for doubt. In view of 
the identity that has been suspected between the Cladodonts and 
Ctenacanthus this point is of considerable interest. The dorsal fins 
are not clearly shown even in those specimens which are lying on 
their ventral faces, but it is scarcely possible to believe that had a 
spine in any degree resembling Ctenacanthus been present its mark 
or its cast must somewhere have been visible. Dr. Traquair evidently 
inclines to this view. In the Gronocican Magazine for February, 
1888, he says, ‘No spine is visible on the Hast Kilbride Cladodus 
but the body is mostly absent.” ‘In the Eskdale Céenacanthus, 
though I interpreted its one imperfect tooth as Cladodont, J am 
willing to leave that an open question.” ‘The teeth found associated 
with Ctenacanthus hybodoides are allied to Hybodus. It has nothing 
to do with Cladodus.” 
In addition to all this the evidence of the Ohio specimens seems 
conclusive that Cladodus was a spineless Shark, whether closely allied 
to Chlamydoselachus or not. The spines, therefore, that occur in the 
Devonian rocks must be assigned to some other fish. Ct. vetustus of 
the Cleveland Shale and Ct. Wrightt of the Hamilton remain un- 
appropriated. 
Another point worthy of notice is the skin of these Cladodonts. 
This on the dorsal surface shows no difference from ordinary 
shagreen. The minute dermal ossicles are smooth, showing in 
most cases little or no sign of sculpture, though occasionally traces 
of a pattern may be seen; but on the ventral surface this shagreen 
is absent, and thin rhomboidal scales supply its place, reminding 
one very much of ganoid plates of great tenuity. These are arranged 
in diagonal lines across the lower surface, exactly as are those of a 
Gar or other ganoid fish. Dr. Newberry has indicated this character 
in his figure, and it is much more evident in some of the recently 
found specimens: apparently it is common to them all. 
In regard to the pectoral fins, the evidence is obscure in spite of 
the apparently excellent state of preservation. There is no trace 
of a median axis or of two rows of rays. The fin is consequently 
not archipterygial in type, and the Cladodonts, therefore, if retained 
among the Ichthyotomi must be considered abnormal. Only a single 
row of fin-rays is present and the basal cartilages on which they 
are set are concealed in the pyritous mass to which the body in 
general is reduced. The full description of the fins must therefore 
await the results of future discoveries. 
The position taken at the outset that the Cleveland Shale is 
intermediate between the true Carboniferous rocks above and the 
true Devonian below will be justified when we consider the strange 
assemblage of fishes whose remains have come to light from this 
stratum. The great Placoderms, Dinichihys, Titanichthys and Gor- 
gonichthys are essentially Devonian in type, and are the analogues 
