618 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
diminish gradually in size, and the base of the fin extends backwards, so that it 
is separated by a short interval only from the base of the tail. 
The caudal fin consists of twenty-one rays; it is deeply cleft into two lobes; 
the external rays of each lobe are about 1:0 inch in length. The base of each 
ray is pointed and attached to the hypural bone as a common centre; the latter 
is a triangularly expanded and flattened plate, with its broad extremity extending 
from the vertebral column towards the tail. The caudal rays rapidly increase in 
size with the expansion of the fin and become subdivided towards their extremities. 
The rays are jointed throughout their entire length; the outer rays of each lobe 
are supported by a series of imbricating rudimentary rays. 
The pectoral fins are large, consisting of thirteen or fourteen rays, the anterior 
ones 10 inch in length. The bones of the scapular arch are proportionately 
strong and indicate considerable power. The articulating surface of the base of 
the fin-rays is produced, rounded, and curved towards the point of attachment. 
The distal half of each ray is divided by bifurcation. 
The ventral fins are similar to the pectorals, except that they are smaller; they 
are attached to pubic bones, which converge and meet on the ventral surface. 
Both fins are exposed in the specimen figured. The scales have a rounded 
posterior outline similar, but somewhat larger and more elongated vertically, than 
those of Rhinellus ferox. 
This short and somewhat ovoid-bodied example is distinguished by the’ great 
proportionate length of the head, combined with the small size and position of 
the orbit, and the dentition of the jaws; these combined characters separate it 
from species hitherto described. The ventral fins are slightly in advance of the 
dorsal, and in this respect it is separated from R. ferox, in which the dorsal fin 
is much further back; the dentition of the two is also unlike. 
Formation and Locality—Upper Cretaceous: Sahel Alma, Mount Lebanon. 
Ex coll.—Lewis Collection, Natural History Department, British Museum, 
Family. HOPLOPLEURIDZ. PIcrer. 
“'Traité de Paléontologie,” 2nd edition, vol. i1., p. 213. 
‘Body generally with four series of sub-triangular scutes, and with inter- 
mediate scale-like smaller ones. One (?) dorsal only; head long, with the jaws 
produced.” 
