620 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
much in size as well as in the details of the form of the scutes; and there can be 
no doubt that the figure given by M. Pictet (op. cit., pl. 1x., figs. 7 and 8) is that 
of a portion of the body of a large fish of the genus Leptotrachelus, and that it is 
the same species as those already included in the species L. triqueter, P. and H. 
Leptotrachelus triqueter, Picrer and HumBeErt. 
(El xccxyalt.,. fio.) 
Leptotrachelus triqueter. Prorer et Humpert, 1866. ‘‘ Nouvelles recherches sur 
les poissons foss. du Mont Liban.,” p. 95, pl. xiv., figs. 1, 2. 
Dercetis triqueter. Picrer, F. J., 1850. 
Fraas, Oscar, 1878. ‘Aus dem Orient. II. Theil. Geolog. 
beobach. am Libanon,” p. 98. 
MM. Pictet and Humbert described the fish remains thus named from very 
imperfect specimens. Since the publication of their memoir others, with much’ 
better preserved characters, have been discovered, and, whilst confirming the 
observations of MM. Pictet and Humbert, afford considerable additional infor- 
mation as to the characteristics of this peculiar fish. The length of the specimens 
varies considerably : an average is about 9 to 12 inches. The specimen represented 
on Pl. xxxvut., fig. 1, is 9 inches in length from the tip of the snout to the base of 
the-tail; the head occupies 1:5 inch, and 1:0 inch must be added for the tail. 
The body of the fish is long and slim; it is highest at a distance of 3:0 inches 
behind the head, where it is 0°6 inch; from this point it becomes smaller towards 
the tail, which is one-third the greatest diameter of the body. Anteriorly the 
trunk becomes rapidly smaller, and a long and slim neck connects it with the 
head; the height of the latter is 0‘7 of an inch behind the orbit, rapidly con- 
verging to the snout. The position and character of the fins is shown in the 
specimen represented. 
The dorsal fin extends 2°4 inches along the back (the length of the fish being 
10 inches); it is 3 inches behind the occipital portion of the head, and is 2°8 inches 
in advance of the tail; the median dorsal surface in front and behind the fin is 
occupied by a series of the tri-pointed scutes characteristic of the genus. 
The anal fin is 1 inch in length, and is separated by a space of 0-6 of an inch 
from the caudal. The ventral fins are 8 inches in front of the anal, and opposite 
to the anterior rays of the dorsal. The pectoral fins are suspended from the 
pectoral arch immediately behind the gill-covers. The body is protected by 
lateral series of tricuspidate dermal scutes, which vary considerably in form, as 
may be seen by reference to the examples figured from several parts of the 
body. 
