t ['in/lot/ us .' magnificus, a New Selachian. — Claypole. L39 
ity to it was a small bony plate or scute, represented in tin- 
figure, nearly two inches in length by one inch wide, with 
vermiculated surface and evidently external. If this is really 
a part of the same fish, as seems highly probable, it indicates 
a much coarser dermic armor on at least a part of the animal 
than the ordinary shagreen of the sharks; but in the existing 
uncertaint} r on this point it would be useless to pursue it 
further. 
Taking the present fossil in connection with its related 
forms which have been described in previous numbers of the 
American Geologist, we can gather one or two important 
facts in regard to the fishes of the Devonian era in Ohio. While 
their kinship with the existing sharks is obvious, they yet show 
considerable difference. In the first place, the position of the 
mouth is strikingly different, so much so as to deprive them 
of the very peculiar and characteristic aspect which we asso- 
ciate with the shark at the present time. The mouth in all 
the recent genera is not terminal but occupies a position con- 
siderably behind the snout on the ventral surface, indicating 
on the part of the animals a habit of feeding on the ground 
or on prey that lies below them. So marked is this feature 
that, as is well known, the shark cannot seize an object on the 
top of the water or above it without turning belly-upward. 
But the Devonian sharks, at. least the eladodonts, had a ter- 
minal or nearly terminal mouth, as indicated plainly in the 
fossils, and were not therefore specially adapted Tor ground- 
feeding. In a few specimens the mouth appears to he slightly 
ventral. In the second place, the jaws of existing sharks are 
strongly curved and twisted, the upper often forming a com- 
plete semicircle, whereas those of the (ladodonts from the 
Devonian of Ohio are straight and flat, and, so far as known. 
the upper jaw was of a similar form. 
It is not necessary to contrasl the narrow elongated phase 
of the tooth of the recent forms with the wide though one- 
sided base of those of Cladodus, since it is well known to 
every ichthyologist. 
If we may infertile size of the fish to which the fossil here 
descrihed belongs, from the analogy with other Ohio clado- 
donts, we may safely predicate a shark not less than ten feet, 
and probably more, in length. So far it is by much the larg- 
