13G 
FISHES OF THE CHALK. 
inch and a half in breadth ; these are probably the 
remains of the tendinous expansion of the muscle 
by which the fin was erected and depressed. 
Of the more perfect fishes, some resemble a 
species of Muraena ; one is decidedly a species of 
Zeus, and is named Z. Lewesiensis in the cata- 
logue. This ichthyolite is related to the genera 
Stromateiis, Chcetodon, and Zeus ; but in its general 
form more closely resembles the recent individuals 
of the latter. 
The fishes of the genus Zeus have the head 
compressed, and sloping, the upper lip arched, the 
tongue subulated, the body compressed, thin, and 
shining, and the rays of the first dorsal fin ending 
in filaments ; in every essential particular of this 
description, the fossil alluded to will be found to 
correspond. 
It is from six to eight inches long ; and its width 
is nearly equal to the length of the body, exclusive 
of the head. It is covered with large, ovate, striated 
scales ; the back and abdomen are ridged, and 
gently arched ; and the body is thin, and com- 
pressed. The head is somewhat obtuse, and large 
in proportion to the body ; the orbits project, and 
are placed high in the head. The lower jaw is 
straight, the upper one slightly arched ; and both 
are destitute of teeth. The opercula hranchialia 
are large, and there are six branchiostegons rays. 
The dorsal and anal fins are placed nearly opjiosite to 
each other, and extend over two thirds of the pos- 
terior part of the body, but do not unite with the 
tail ; the rays of the dorsal fin appear to pass into 
long filaments, as in the recent Dory. The pectoral 
