Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 539 
of the peduncle of the tail, and the relative position of the dorsal and anal fin. 
In this species the anterior rays of the dorsal fin are inserted further behind 
the head than in Pycnosterinx heckelii. These characters will also distinguish 
it from P. dorsalis, Pictet. I have much pleasure in dedicating this species to my 
friend Mr. William Davies, of the British Museum, to whom I have repeatedly 
been indebted both for the benefit of his ripe experience, and to his knowledge of 
the magnificent collection in which he takes so great an interest. 
Formation and Locality.—Upper Cretaceous: Sahel Alma, Mount Lebanon. 
Ex coll.—British Museum, Natural History Department. 
Pycnostering gracilis, DAvis. 
y WIV . 
(Pivpscx,, ie. 1) 
Body elongated oval. Length, with the exception of the tail, 3-8 inches, 
including the head, 1:8 inch; the tail is an additional 1:5 inch. Its greatest 
height is 1:7 inch, at the base of the dorsal fin, midway between the two 
extremities. The body is well preserved, except the anterior portion. The 
cranial surface is absent, and the lower posterior part of the head is much 
disturbed. The orbit is large, placed rather forwards. The jaws are strong, 
capable of considerable expansion, and in both the upper and lower there are 
minute, pointed teeth, scarcely visible without the aid of a lens. The pre- 
operculum is broad in the median part, diminishing in width slightly towards 
the occipital region, and much more so in the lower part; it is larger than 
the operculum, which is displaced and pushed backwards. 
The vertebral column comprises twenty-eight vertebrae, of which fifteen are 
caudal. They are not so high as long, and contracted medially. The neural 
spines are comparatively short, extending about half the distance between the 
vertebrze and the dorsal fin. The interneurals are proportionately large, and 
their exposed base forms a broad articular surface for the rays of the fin. The 
hemal spines are longer than the neurals, and thicker; they are less numerous 
than the interhemal spines, as are also those on the neural side than the 
interneurals. The ribs are short and, so far as can be distinguished, feeble. 
The dorsal fin extends from the peduncle of the tail 1-5 inch; its anterior 
rays are 2°5 inches behind the snout. The first six rays are spinous and 
imbricating; those succeeding, twenty-six in number, are articulated. ‘The first 
of the soft rays is 1:3 inches in length; from this they gradually diminish, the 
posterior being 0°15 inch. The anal fin has a basal length of 1:3 inch: its 
anterior rays, 2°5 inches from the snout, exactly the same as the dorsal. Three 
or four of the anterior rays appear to be spinous, but the whole fin is so much 
broken that it is difficult to make out its several parts. The caudal fin is deeply | 
