FISHES OF THE CHALK. 
143 
a scabrous reticulated appearance, not unlike the 
surface of some kinds of Balistes. The head is an- 
gulated ; the orbits large ; the opercula smooth, 
and rounded ; the jaws dentated, and nearly 
straight. The teeth in the upper maxilla are 
conical, pointed, and rather flat ; there are about 
forty on each side, of which the eight or nine ante- 
rior ones are the largest. Those of the lower jaw 
are exceedingly small, and very numerous. The 
dorsal fins are two in number ; the anterior one is 
placed in a sulcus, or groove, in the back, and ap- 
pears to have been capable of erection or depres- 
sion ; it consists of eight strong rays, the two first 
being garnished with spines. The posterior dorsal 
fin is remote from the other, and composed of nu- 
merous delicate rays. The pectoral fins are placed 
on the thorax, near the lower margin of the oper- 
cula. The ventral fins are attached to the abdomen, 
opposite to the anterior dorsal fin ; and the anal fin 
to the posterior one. The tail appears to have been 
rounded, but no perfect specimen of this part has 
been obtained. The tongue is occasionally pre- 
served ; it is of a triangular form, and its surface is 
covered with numerous papillae. The air bladder 
is of an elongated oval shape, and lies in the abdo- 
men, immediately beneath the spine.* 
From the preceding description, which compre- 
hends all that is at present known concerning this 
* It may seem scarcely credible, that a part of such delicate struc- 
ture should be preserved in a mineralized state, yet the fact is unques- 
tionable; I have several specimens in my collection, in which it is clearly 
shown ; and also the coprolites or fossil faecal contents of the intestinal 
canal. 
