Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 615 
The dorsal fin is not clearly preserved, only the posterior portion of rays 
remain; this, combined with the evidence of another specimen about the same 
size, shows that its posterior was about 4 inches behind the head. The pectoral 
fins are situated abdominally immediately behind or under the operculum; the 
ventrals are 2°6 inches behind the pectorals; the distance between the insertion 
of the ventral fins and the anterior ray of the anal is 3 inches, and thence to 
the base of the tail 1°5 inch. 
The head is equal in length to the body. The orbit is large ; it is 4:5 
inches behind the tip of the snout, 0°8 of an inch in diameter, situated high in 
the head, leaving a very small inter-orbital space. The post-orbital area extends 
1:5 inch between the orbit and the posterior margin of the operculum, and its 
height is 1:2 inch. Nearly the whole of this space is occupied by the operculi. 
They are not sufficiently well preserved to be distinctly identified, but they are 
rounded posteriorly, and were encased in a smooth coating of enamel. The 
branchiostegal apparatus is not exposed. The jaws are long and slender, in 
the specimen of which a figure is given (Pl. xxxvu.), the rami of the jaws 
have become separated; those of the lower jaw are longer than those of the 
upper one; it is doubtful, however, whether this may not be simply due to want 
of care on the part of the person who has prepared the specimen. The articu- 
lating extremity of the mandible is strong, rounded, and prominent, and is 
attached to the skull 0-2 inch behind the orbit. ‘The dentition of the upper and 
lower jaws is dissimilar. The teeth of the upper jaws are longer than those of 
the lower one; they consist of laniary teeth, 0°15 of an inch in length near the 
base of the jaw, but becoming gradually shorter towards the extremity; they are 
small in diameter and acutely pointed, very slightly curved inwards; between 
the larger teeth are others much smaller, but similar in form, and averaging 
three in number. The teeth of the lower jaw are smaller than those of the 
upper; the small teeth between the laniaries are very small; whilst the latter 
are not so much as half the length of those of the upper jaw. 
The vertebral column consists of forty-eight vertebree ; those situated anteriorly 
are 0-2 inch in length; the articulating surfaces are equal in diameter to three- 
fourths the length; the vertebre decrease in size towards the caudal extremity. 
The neural spines are bifurcated at their base, long, and slender, numerous, with 
branching apophysial bones. Strong interneural bones, with broadly-expanded 
base, support the dorsal fin. The ribs are less numerous and stronger. The 
hemal spines partake of the character of the ribs, and a series of small inter- 
heemal spines support the rays of the anal fin. 
The dorsal fin, in the specimen drawn on Pl. xxxvil., is absent ; it is preserved 
on a second specimen in the National Collection; it was large, supported by 
strong fin-rays; their entire length is not shown; they probably numbered 
402 
