564 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
lengthened and less in diameter ; the extremity of the vertebral column is turned 
towards the upper lobe of the tail. The ribs are long and slim. The neural and 
hzmal spines are thicker than the ribs, and extend obliquely backwards. Inter- 
neural spines support the rays of the dorsal fin, and interhzmal ones those of the 
anal fin; of the former there are about fifteen, and of the latter fourteen; they 
are very fine and, the body being covered with scales, can only be observed after 
careful examination. 
The dorsal fin was large, and situated behind the ventrals; its anterior rays 
are midway between the ventral and anal fins, and, estimating from the number 
of interneural spines, it would contain about fifteen rays; of these, the anterior 
ones only are shown in the specimen. ‘They are 0°6 of an inch in length, and the 
first ray is supported by a few short imbricating rays. The anal fin is not pre- 
served, but its position is indicated by the interhzemal rays. It was 0°4 of an 
inch in length, and its posterior extremity 0-4 inch in advance of the tail. The 
caudal fin is forked ; the lobes are of equal length. The fin consists of twenty- 
three rays; they are jointed, and bifurcate towards their extremities. 
The pectoral fins are situated on the abdominal surface of the body. The rays 
of the one exposed are closed, so that their number cannot be ascertained; the 
fins were large, and quite half an inch in length. The ventral fins are also 
attached to the abdominal surface; they are considerably in advance of the 
dorsal fin. 
The scales are large; the outer margin is more or less semicircular; the 
median portion of the margin is produced, so as to form a small point. The 
scales are enamelled and smooth. Their number is not easy to count, but there 
were probably twelve in a transverse line on the anterior part of the body. 
This species may be readily distinguished from others previously described by 
its small size, the small number of the vertebre in the spinal column, the relative 
position of the dorsal to the ventral and anal fins, and the character of its scales. 
The latter, though of the same outline as those of O. lata, in this species are smooth, 
whilst those of O. lata are ridged; other species are ridged, or have a serrated outline. 
The first characteristic named, that of its small size, if unaccompanied by others, 
might be simply taken as indicating immature growth, but taken in conjunction 
with the fewness of its vertebrae, which only number about two-thirds those of 
some other species, and the short dorsal fin placed posteriorly, and the general 
aspect the fish presents of maturity, leads to the conclusion that it forms the type 
of a distinct species. 
Formation and Locality.—Upper Cretaceous: Sahel Alma, Mount Lebanon. 
Ez coll.—R. Damon, Esq., Weymouth. 
