Davis—On the Fossil Fishes of the Chalk of Mount Lebanon, 591 
Spaniodon hakelensis, Davis. 
(Pl. xxxtv., fig. 4.) 
The specimen is well preserved, except the anterior portion of the head. It 
has a long and slim body, with strong dorsal and caudal fins; it is 5 inches in 
length, exclusive of the tail, and of this length the head takes up one-fourth. The 
height at the base of the anterior rays of the dorsal fin is 0°5 of an inch, and this 
is maintained anteriorly to the head and posteriorly to the base of the anal 
fin ; thence it contracts to the peduncle of the tail, which is 0°3 of an inch. The 
scales are not well defined, but appear to have been small and thin. 
The bones of the head are partially displaced; the orbit is medium-sized, 
situated rather high, otherwise centrally ; it is surrounded by strong infra-orbital 
bones; the post-orbital area is large, the operculum somewhat angular on its 
posterior margin. ‘The mandible is not shown, but the displaced quadrate 
indicates a strongly articulated bone; the snout extends 0°5 of an inch beyond 
the orbit. 
The spinal column is composed of forty-four vertebra, of which thirteen are 
caudal; the vertebree are large and strong, deeply bi-concave, and about as broad 
as high. The ribs are short and slender; the abdominal cavity enclosed by them 
is long, but shallow. ‘The neural and heemal spines are much thicker than the 
ribs; they are strongly attached to the spinal column by apophyses, especially 
towards the tail. Eleven interneural spines give support to the dorsal fin, and a 
supplementary plate extends horizontally from the most anterior one; the anal fin 
is similarly supported by seven interhzemal spines. 
The dorsal fin is 1:3 inch behind the head; its base extends 0:75 of an inch 
along the ridge of the back; it has twelve rays, of which the anterior ones are 
longest 0°7 of an inch. The anal fin has nine rays, smaller and shorter than the 
dorsal; its anterior ray is midway between the ventral and caudal. ‘The caudal 
fin is large; its base is formed by a series of radiating hypural plates, connecting 
the caudal rays with the vertebral column; the caudal rays are jointed and 
bifurcate towards the distal extremity ; the external ones are longest and thickest, 
being at least an inch in length. ‘The tail is forked, but not very deeply. Both 
the superior and inferior margins are supported by a series of imbricating 
rudimentary caudal rays; those at the base of the upper lobe are twelve in 
number. 
_ Of the paired fins, the pectorals are supported by a strong scapular arch, 
forming an angular series of bones encircling the posterior outline of the operculi. 
The pectoral fins consist of eight or ten fin-rays, 0°4 of an inch in length. The 
ventral fins are 1-5 inch behind the base of the pectorals; each is supported by a 
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