Cladodont Sharks. — Clay pole. 327 
Near the tail the lateral margins of the body spread out horizon- 
tally, forming a membranous flap in structure resembling the mar- 
gin of the pectoral fins but without rays. 
No sign of a dorsal fin is shown unless it be where the caudal 
fin mentioned above is described. No trace of spines is seen in 
anj^ part of all the specimens examined. Possibly there is some 
error on this point in the figure of C. fyhri given by Dr. New- 
berry. 
Cladodus clarki. 
Fish about forty-five inches long, body slender, about seven 
inches wide. Head pointed in front, widening between jaw and 
pectoral fins. Pectoral fins shaped nearly as in C. l-ejderi, six 
inches long by four and a quarter inches wide at base; front 
edge about eleven inches behind snout; rays about eighteen, strong, 
the larger forking toward the tip. 
Teeth numerous, each with a single large denticle on each side 
of the median cusp and of about half its length, smooth, with 
slight longitudinal lines, but not striate; very small intermediate 
denticles at base. 
Head covered with fine smooth shagreen. Ventral surface with 
scales similar to those of C. kepleri. Skin on lower side of neck 
transverseh^ striate. No trace of notochord visible. Ventral 
fins soft and showing scared}' an}^ trace on the fossil. Hinder 
end of body not j'et found. 
In the abdomen of the first specimen discovered lies a large co- 
prolite showing a spiral line apparently indicating the print of the 
intestinal valve of the sharks. 
Branchial openings five, plainlj- visible just in front of the pec- 
toral fins. 
Cladodus sinuatus. 
Fish about thirty inches long (tweut3'-six inches preserved); 
body less slender than in the foregoing species, expanding, at least 
in the fossil, behind the pectoral fins and then rapidly tapering 
backward, the greatest width being nearl}' five inches. 
Head as preserved showing a very marked doubl}' curved out- 
line which is probably exaggerated by compression, the snout pro- 
jecting strongly forward and extending six and a half inches in 
front of the pectorals. 
Pectorals nearly straight in front (in the figure the concave 
curve is too strongly marked); margin membranous and some- 
