Cladodont Sharks. — Claypole. 329 
inches wide at base; tips of both missing; ra^'s seventeen or eigh- 
teen, radiating from the middle of base, margin slightly mem- 
branous. One of the ventral fins is slightly shown with eight or 
nine rays. 
In the place where the stomach of this fish la}- during life is a 
mass of thin ganoid scales, among which close examination re- 
veals a thin and slender jaw set with fine sharp teeth. Obviously 
we have here the half digested relics of the last supper of the 
shark and at the same time a proof of the coexistence of a ganoid 
fish of which we had previously no knowledge. The remains 
scarce!}' admit of description or definition but the shark has thus 
unwittingl}- preserved for us a trace of other ichthyic life 3-et to 
be found in the Cleveland shales. Behind the stomach are the 
fossilized coprolites including fragments of a similar natui-e in a 
more advanced stage. 
I have named this species f i*om the Rocky river, where the fossil 
was found hy Dr. Clark. 
MONOCLADODUS. 
One of Dr. Clark's specimens shows, in spite of the necessar}' 
indistinctness incidental to a pyritized fossil, points of difference 
so strongly accentuated that it cannot strictly be included in the 
same genus as those alread}^ described. Yet in general appear- 
ance it so closely resembles them as to indicate a very close rela- 
tionship. The chief difference lies, as will be seen in the descrip- 
tion given below, in the teeth, and for these reasons I have chosen 
the term Monocladodus for the fossil. 
In mere size this fish is very distinct, far exceeding all those 
above described and this character would suffice for specific dis- 
tinction. But the marked divergence in the form of the teeth 
seems to warrant something more than this. Though a few so-called 
Cladodus teeth are known in which the lateral denticles are ex- 
ceedinglj' small, and perhaps one or two in which no traces of them 
can be seen,3-et it seems on the whole preferable to adhere to the 
technical description and exclude from Cladodus all that do not 
exhibit them. 
Ivlonocladodus clarki. 
Fish about 63 inches long, slender, about eight inches in great- 
est width behind the pectorals. Head rounded in front, some- 
what sinuous at the sides, constricted in front of the pectorals. 
Pectorals very large and strong, eight inches long by five and a 
