Three Great Fossil Placoderms of Ohio. — Claypole, 97 
former in size (the jaws found being 24 inches long) it surpassed 
it in bulk and weight. The description given of Diniehthys will 
suffice for the front teeth of this species so far as yet known. 
but there are no shear-blades behind them to rut and slice the 
prey. On the lower jaw is a blunt projecting point on which 
fits a powerful two-pointed tooth corresponding to the round- 
edged cutting plate in the upper jaw of Diniehthys. though 
in neither case has it yet been found exactly in life position. The 
tooth measures 9 inches horizontally and 7 inches vertically, 
and as an instrument of offence it must have surpassed in 
power and destructiveness the cutting shears of Diniehthys 
terrelli. 
To this monster of the ancient sea. considering that Dr. N. 
has had already the pick of the classic nomenclature, has been 
applied the generic name "Gorgonichthys," and in apprecia- 
tion of the amount of time and labor that its discoverer has 
-pent upon its extrication it is only just that the specific term 
should memorialize his patience and skill. The fish, then, of 
which I lately gave a preliminary notice, is known as Gor- 
gonichthys Clarki. It was found in 1891. 
Our readers are now prepared to understand in part, at 
least, the significance of such discoveries as these. The exist- 
ence of predaceous fishes implies the existence of others on 
which they could prey, and so again of other creatures and 
plants to support these. In imagination, then, we can see the 
waters of this Appalachian gulf swarming with life that has 
passed away, and whose remains, if not totally destroyed, will 
one day be found. Their existence, however, is not one whit 
less certain though their forms should never become known. 
The creation of this numerous fleet of armour-clad beings 
from the scattered fossil remains of the Devonian strata of 
Ohio is in keeping with similar discoveries elsewhere espec- 
ially in Scotland where the work of H. Miller in the Old Red 
Sandstone has made the subject and the ground alike classic. 
It was a singular stage in the evolution of fishes. Nature 
apparently loaded these small brained creatures with all the 
protective armour that they could carry, and it would seem ;i- 
if she had reached at last a limit beyond which it was impos- 
sible to increase it without destroying the buoyancy of the 
fish. Just as now the navies of the world are loaded down 
