486 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
outline, much less rounded or semicircular than in the preceding species. The 
ventral fin is supported by the pubic bones connected with the vertebral column 
at a distance of 2 inches behind the pectoral arch; it is 2 inches along the 
base, and extends 1 inch laterally from the body of the fish. The number of rays 
supporting the fin are not well defined, but the impressions produced by eighteen 
can be identified on the dermal covering. The unpaired fins are not present. 
This species differs from those previously described in the widely expanded 
body, the broad triangular outline of the pectoral fins as compared with the 
elongated and circular form of R. grandis. 
Formation and Locality.—Upper Cretaceous, Sahel Alma, Mount Lebanon. 
Ex coll.—Lewis Collection, British Museum. 
Rhinobatus expansus, Davis. 
(Pl. xvi.) 
The beautiful specimen which forms the subject of the following description, 
as well as the type of the species last described, R. latus, were collected 
by Mr. Lewis during his sojourn at Beyrout. This specimen is distinguished 
by the immense expansion of the pectoral fins, comparatively small ventrals, 
and attenuated tail. The fish is not quite perfect, as a portion of the snout 
and the extremity of the tail are wanting. The length preserved is 9°5 inches. 
The width across the pectoral fins is 10 inches. The dorsal surface of the 
fish is exposed. The dermal covering is in part preserved: it is thinner, but 
otherwise similar to that of R. latus. The width at the base of the tail is 
0-9 of an inch. 
The spinal column exhibits seventy-three vertebrae, but is imperfect at the 
caudal extremity. The vertebre are higher than long, the median portion 
much contracted. The thoracic vertebree support twenty-four ribs on each side; 
the thoracic cavity is comparatively small and narrow. 
The head occupies a length of 3 inches from the snout to the pectoral 
arch, and is 2°5 inches across. The orbits are large and round, 0°5 of an inch 
in diameter; they are situated 1 inch behind the snout, and are separated 
by a distance of 0:4 of an inch. The post-orbital region is not preserved, and 
the form of the snout, which was more or less pointed, can only be ascertained 
by inference. The buccal armature, by reason of the position of the fish, is 
not exposed. 
The pectoral fins are widely expanded: they extend from a position 0°5 of 
an inch anterior to the eyes backwards for 5°5 inches, and from the body 
to the lateral extremity of the fin is 4°5 inches. The outline of the fin is 
triangular, culminating laterally in a somewhat acute point; from the head to 
this point the outline is slightly convex, thence posteriorly it forms a gracefully 
