MURiENID-E. 
337 
Genus URENCHELYS, A. S. Woodward. 
[Ann. Mag. Nat. Hist. (7) vol. v. 1900, p. 322.] 
Teeth small, bluntly conical, and arranged in numerous series. 
Slender branchiostegal rays not curving round the opercular 
apparatus. Vertebra; somewhat exceeding 100 in number, the 
hindermost bearing a pair of expanded hypural bones. Pectoral 
fins present; dorsal fin arising immediately behind the occiput and 
extending to the caudal fin, which has stouter rays and is very 
small but separate. Scales rudimentary. 
Urenchelys avus, sp. nov. 
[Plate XVIII. figs. 1, 2.] 
•type. Imperfect fish ; British Museum. 
The typo species, attaining a length of about 0'3. Length of 
head with opercular apparatus contained about six times in the 
total length to the base of the caudal fin ; anal fin considerably 
more than twice as long as the portion of trunk in front ot it. 
Anterior neural arches much expanded, their appended spines 
apparently small and low. 
Form, Loc. Upper Cretaceous : Sahel Alma, Mount Lebanon. 
P- 4860. Type specimen, shown of the natural size in PI. XVIII. 
fig. 1. A few of the blunt teeth are seen among the 
fractured remains of the cranium ; while below it the 
extent of the mandible can be distinguished. The 
branchial region is probably shortened by crushing, and 
remains of the very slender branchiostegal rays lie across 
fragments of the branchial arches and the rather stout 
clavicle. The vertebra; cannot be readily counted, but 
there seem to bo about 35 in front of the origin of the 
anal fin, and not less than 73 beyond. Ihe neural 
arches in the abdominal region are very stout laminae, 
but their spines are not seen. The transverse processes 
and very short slender ribs are distinct. The long 
slender neural and haemal spines in the caudal region are 
also conspicuous. The pectoral fins aro not preserved. 
The dorsal fin clearly arises directly above the pectoral 
arch, extending continuously along the back to the caudal 
extremity, while the remarkably extended anal fin is 
continued equally far backwards. There are distinct 
indications of two expanded hypural bones at the tip of 
fart iv. z 
