Actinophorus Clarki, Neirherry. — Cloy pole. 21 
scription, about eighteen inches or two feet in length, but 
these uieasurements must be somewhat increased if we may 
judge by the size of the jaw of the new fossil which, when 
compared with that of Dr. Newberry's is at least one-third 
longer. The whole hinder part is missing, but the body is 
fairly preserved as far back as the ventral fins which are in 
part visible. The most conspicuous and the best preserved 
portions are the jaws and the pectoral fins. The jaws of the 
right side are almost perfect, lying closed and spread out on 
the stone. Those of the left side are crushed and concealed 
beneath them. The former aspect of the fossil is represented 
in our figure, where very little has been attempted in the way 
of restoration beyond supplying one or two teeth from the 
opposite jaw and setting in its original position the nasal or 
intermaxillary bone which had been fiattened down. 
The mandible in its general form agrees with that of the 
cladodont sharks as figured in one of our previous notes but 
it has little of the corrugation that is so conspicuous there 
and was consequently inferior in strength-and stiffness though 
this lack was in part made up by a greater thickness. Its 
surface, in the hinder part at least, is marked with a fine and 
simple tuberculation. The broad thin blade of which pos- 
teriorly it consists thickens forward, especially upon its upper 
margin, so as to afi:ord a broad base for the support of the 
teeth. Most of these have disappeared but one or two remain 
in place and resemble those of the upper jaw where most are 
still visible. They are simple, conical cusps, not true teeth, 
because the}^ are not by nature epithelial but consist of in- 
tegral parts of the jaw, as do the teeth of Coccosteiis, being 
as it were excavated from that bone. Eight or ten of them 
stood in a row distant from each other about a half-inch and 
locked in, closing between those of the opposite jaw. Their 
form is that of a round cone slightly flattened laterally at the 
base. They are quite smooth and unstriatcd. 
Behind these and along the upper margin of the mandible 
is an irregular row of snuill, fine, sharp denticles very distant 
from one another. They occup}^ about an inch and a half of 
the jaw and disappear where the nuixillary closes down out- 
side of the mandible. If they continue farther back they are 
concealetl V)y this bone. 
