Prof. EL. W. Claypole— Upper Devonian Fishes of Ohio. 445 
It is a little surprising that at last the material for enabling us 
further to realize our picture should have come from these long- 
called barren shales of Ohio. But during the past two years an 
enthusiastic and patient collector, Dr. Clark, has brought to light a 
number of specimens in a wonderfully good condition considering 
the pyritized state of all the fossils from this stratum. By dint of 
great labour he has so far cleared them from the matrix that I have 
been able to describe at least five species in addition to the one 
figured by Dr. Newberry. The details may be found in the 
American Geologist for May, 1893. It is not my intention here to 
dwell upon the specific distinctions of these fishes, but to point out 
a few interesting facts and inferences in the paleontological history 
o the Cladodonts. 
Fie. 1.—Head, pectoral fins, and abdominal region of Cladodus rivi- 
petrosi, Claypole; with two teeth enlarged. 
The figures given herewith will enable the reader to form some 
idea of their general shape, at least as they are preserved in the 
fossils. All the specimens yet discovered present either the dorsal 
or the ventral aspect, in almost all cases the latter. The Shark 
apparently settled down in that position on dying, perhaps owing to 
the accumulation of gases in the abdominal region. 
The most obvious unusual feature is the expansion of the head. 
This is so much wider than the body that the fish appears to have a 
neck in some cases, as in C. sinuatus, etc. In others the constriction 
is less, while in some it is almost absent. The suspicion is of course 
aroused that it may be a result of something in the process of 
fossilization, but an examination of the specimens renders this un- 
likely. It is not, apparently, due to pressure or distortion. 
Among existing Sharks it is not easy to find any structure that 
when fossilized would show a similar form. But the Bonnet Shark, 
or the Shovel-nosed Shark (Reniceps tiburo), may be quoted as an- 
illustration of a fish that in outline, as seen from above, might 
produce an impression resembling the one in question. On a side 
