ESPECIALLY MYCTOPHOIDS 141 
Phylactocephalus microlepis Davis 
(Text-figs. 65, 66) 
1887 Phylactocephalus microlepis Davis : 605, pl. 35, fig. 2. 
tgot Halec microlepis (Davis) Woodward : 218. 
Diacnosis (emended). Phylactocephalus of standard length not exceeding 18 cm. 
Length of the head with the opercular apparatus just exceeds the maximum depth 
of the trunk. Length of the mandible equivalent to the depth of the head at the 
occiput. Vertebrae 32 in number of which 16 are caudal. Dorsal fin with 17 rays 
occupying the second quarter of the back. Anal fin small and remote with II rays. 
HoLotypPe. Specimen number P.4757 in the B.M.N.H., a complete but flattened 
fish from the Middle Cenomanian of Hajula, Lebanon. 
MATERIAL. Holotype and several other specimens in the B.M.N.H., numbers 
P.105, P.46453, P.47318 from the Middle Cenomanian of Hakel ; P.47329 from the 
Middle Cenomanian of Hajula, Lebanon. 
REMARKS. The type specimen was initially poorly described by Davis (1887 : 
605, pl. 35, fig. 2). His description was later corrected by Woodward (1901 : 218) 
when he transferred the species to the genus Halec. The type specimen was 
developed in acetic acid by the transfer method together with a complete, exception- 
ally well preserved specimen, number P.105. Since all the material is flattened, 
neurocranial description is difficult, however the postero-lateral region of the skull- 
roof is partially shown in specimen number P.47318. 
DESCRIPTION. Neurocranium. The majority of the skull-roof is formed from 
the enlarged frontals which extend posteriorly almost to the occipital border. 
Laterally the frontal is curved above the orbital region to overlap the dorsal surface 
of the sphenotic and form the hind end of the orbit. Postero-laterally the frontal 
is deeply indented, and this marks the anterior extent of the unroofed post-temporal 
fossa. The frontals are uniformly ornamented with minute bony tubercles. In the 
snout region the frontals curve antero-ventrally. The sphenotic projects from 
beneath the frontal at the rear end of the orbit. The pterotic forms the postero- 
lateral border to the neurocranial roof, contacting the frontal and parietal medially. 
The dorsal surface of the pterotic has a prominent longitudinal crest which separates 
the post-temporal fossa from the dilatator fossa. The crest has a small posterior 
foramen which transmitted the lateral line canal into the pterotic. Ventro-laterally 
the pterotic has an elongated groove and this represents the hind region of the 
hyomandibular facet. Anteriorly the hyomandibular facet is cup-shaped and 
formed of sphenotic and prootic. 
Within the orbit the parasphenoid is slightly curved and possesses small ventro- 
laterally inclined flanges. Towards the snout the parasphenoid flattens where it 
contacts the vomer. The vomer appears to contact the underside of the mesethmoid 
anteriorly and has slight lateral extensions which parallel those of the mesethmoid. 
Hyopalatine bones. The hyomandibular is large and has a double head. The 
posterior part of the head is elongate and lies in a horizontal plane but the anterior 
