Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 505 
the tail is perfect. The greatest length on the ventral surface is 7-5 inches; the 
extremities of the two lobes of the tail are 4:0 inches apart, the peduncle of the tail 
2:0 inches in height, which increases anteriorly. The caudal portion of the vertebral 
column is preserved, and numbers thirty-two vertebra; the extremity hetero- 
cercal. The vertebra are large, higher than broad. Neural and hemal spines 
extend from each vertebrae. A number of interneural spines support the dorsal 
fin, of which fifteen can be distinguished. Interhzmal spines, eight in number, 
support the anal fin. 
The anal fin is situated 28 inches from the caudal. It comprises eight rays, 
portions of which are now in fragments; the rays were probably 1:5 inch in 
length, and are articulated and branching. The dorsal fin is broken away; only 
three posterior rays remain, similar to the anal. The caudal fin is strongly 
supported by processes extending from the vertebral column to the rays of the fin, 
decreasing in length near the end of the spine. ‘The rays composing the fin are 
twenty-one in number, and are all supported from the lower convex surface of 
the spinal column; they are thick near the base, but rapidly bifurcate and become 
divided into numerous filamentous rays, whose posterior margin forms a slightly 
concave outline to the fin. Numerous rudimentary rays extend from the upper 
concave surface of the vertebree and form a strong support to the upper lobe of 
the fin; a number of rudimentary rays also support the lower lobe. 
The ventral fin is 20 inches in advance of the anal; it is supported by a 
horseshoe-shaped bone, a portion of which only is preserved. The fin is 1°6 
inch in length, and consists of fourteen rays, which become rapidly divided 
into several times that number. 
Formation and Locality —Hard chalk: Hakel. 
Ex coll.—Lewis Collection, Natural History Museum, South Kensington. 
Sub-class IIL—TELEOSTEI. 
‘‘Heart with a non-contractile bulbus arteriosus; intestine without spiral 
valve; optic nerves decussating ; skeleton ossified, with completely formed 
vertebrz ; vertebral column diphycercal or homocercal; branchie free.” 
(Giinther. ) 
The Teleostei are divided by Dr. Giinther into six orders, as follows :— 
I. Acanthopterygil. 
II. Acanthopterygii pharyngognathi. 
III. Anacanthini. 
IV. Physostomi. 
V. Lophobranchi. 
VI. Plectognathi. 
