562 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
greatest height, in front of the dorsal fin, is 18 inch; thence the body and head 
gradually contract, the latter terminating in a broadly-expanded snout. The 
peduncle of the tail is 0°8 of an inch in height. The height is greater in 
proportion to the length than in any other species. 
The vertebral column consists of fifty-eight vertebra: the articulating surfaces 
are expanded ; the intermediate portion is contracted and fibrous. Twenty of the 
vertebree are caudal. The ribs are not well defined, but were long and fine. The 
hzmal and neural spines are short and strong, those supporting the caudal rays 
more especially so. Interneural and interhzemal spines support the dorsal and 
anal fins. 
The head, during the deposition of the fish, has been turned over, so that the 
upper surface of the cranium is exposed. The width of skull between the orbits 
is 0-4 of an inch; the orbit is 0°5 of an inch behind the extremity of the snout; it 
is large, and surrounded by bones of considerable strength. The opercular appa- 
ratus is fully developed, about an inch in diameter, with convex external margin, 
and the anterior one concave. The gape was wide, extending backwards beyond 
the orbit. The alveolar margin‘of the lower jaw is exhibited; it contains the 
bases of a number of teeth. The external bones of the head were enveloped in a 
thick coating of shining enamel. 
The dorsal fin is 2:1 inches behind the head; it extends 1:2 inch along the 
back. The number of rays cannot be determined, but they are strong near the 
base, and supported by imterspinous bones. The anal fin numbers seven rays, 
divided towards their extremity ; it is situated 1°3 inch in front of the caudal, and 
is separated by 2-3 inches from the ventral. The caudal fin is large and powerful ; 
it consists of about thirty-two rays, divided between the two lobes. Extending 
from the end of the vertebral column there are strong bony rays, branching to 
each lobe of the tail, and from these spring others diagonally ; the rays dicho- 
tomize, and are articulated at short intervals. Short fuleral rays support the 
external rays of the upper and lower lobes of the tail. 
The paired fins are comparatively small and feeble. The pectorals are situated 
on the lower lateral surface, immediately behind the opercular bones. Each consists 
of fourteen rays, at first undivided, but more distally, articulated at short intervals, 
and frequently dichotomizing; the longest rays are 1:1 inch in length. The 
ventral fins are placed nearer the median abdominal surface than the pectorals ; 
they contain eight rays each, and are smaller; otherwise the two pairs of fins are 
similar. The ventrals are rather in advance of the dorsal fin; they are midway 
between the pectorals and the anal fins, being separated from each by 273 inches. 
The scales are elongated, and oval in outline, the greater axis being 0°2 of an 
inch in diameter. The surface is covered with radiating ridges, which, produced, 
form a crenulated margin; the middle ridges are somewhat longer than the 
others, and their extension induces an acuminate projection of the median 
