496 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
seen internally, these continuous lines decussate with the true vertebral apophyses, 
and cause the regular lozenge-shaped pattern so characteristic of the Pyenodont 
family.” In the fossil remains of this group it not unfrequently happens that 
the skeleton of the fish is preserved, whilst the scales have been removed or 
are not preserved, though the ‘thick solid bony ribs,” described by Sir P. 
Egerton, still remain, or have left a very distinct impression on the matrix, 
crossing the spinous apophyses diagonally (see Pl. xxi, fig. 1). This serves 
to explain the difficulty experienced by Agassiz, who states (op. c7t., p. 185 and 
p- 204) that the singular bones prolonged obliquely across the apophyses and 
sometimes also across the ribs are the most remarkable feature in the skeleton 
of these fishes, of which there is no representative in living fishes. There can 
be no doubt the cross pieces are the thick ribs detached from the under surface 
of the scales. 
Hitherto no fossil fish remains of the order Ganoidei have been with 
certainty identified from Mount Lebanon. Considerable uncertainty exists as 
to the true position of the genus Leptotrachelus; it is the more satisfactory, 
therefore, to find the following representative of the Ganoidei in the hard 
chalk of Hakel, and to express the indebtedness of ichthyologists to the Rey. J. 
E. Lewis for his valuable service in collecting the specimens. 
Genus. Paleeobalistum. DE BLAINVILLE. 
Body more or less circular, adpressed. Head large, profile, almost vertical. 
Orbit large, very high. Mouth placed near the base of the head, slightly 
prominent; teeth situated on the vomer and on each of the maxillaries: there 
are rows on each mandible, all nearly equal in size, circular or cresentic. 
Dorsal and anal fins, commencing near the middle of the body, extend to the 
base of the caudal, the latter short, but widely expanded. Paired fins small. 
Paleobalistum geedelli, HECKEL. 
(Pl. xxu., figs. 1, 1a.) 
Specimens vary from 9 inches to a foot in length. The one now described is 
9 inches from the snout to the base of the tail. The latter is 13 inches in 
addition ; its form is ovoid, tending to rotundity ; the greatest height is 7 inches, 
exclusive of the fins, midway between the head and tail. Posteriorly the height 
is rapidly diminished to the peduncle of the tail, which is 0°5 inch. ‘The anterior 
margin is rounded, with a slight prominence of the buccal orifice. The head 
is large, and occupies one-third of the length of the fish. Dorsal and anal 
fins of considerable extent envelop the, posterior margin of the body to the 
