ESPECIALLY MYCTOPHOIDS 179 
Genus PRIONOLEPIS Egerton, 1850 
DraGnosis (emended). Prionolepididae in which the head and body are slightly 
elongated and somewhat laterally compressed. Teeth extremely numerous on the 
vomer, palatine, ectopterygoid and dentary ; all teeth long, thin and needle-like 
and noticeably recurved. Vertebrae as long as deep with mesially constricted 
centra. Paired fins large, pectorals slightly larger than the pelvics. Pelvic fins 
opposed to the hinder part of the dorsal fin. 
TYPE SPECIES. Prionolepis angustus Egerton. 
Prionolepis cataphractus (Pictet & Humbert) 
(Text-figs. 83-85) 
1866 Aspidopleurus cataphractus Pictet & Humbert : 109, pl. 18, fig. 1. 
tgo1 Prionolepis cataphractus (Pictet & Humbert) Woodward : 230. 
Woodward lists the earlier references. 
DiaGnosis (emended). Prionolepis of standard length not exceeding I9 cm. 
Length of head with opercular apparatus less than half the length of the body. 
Maximum depth of the trunk one-seventh of the body length. Dorsal fin with 18 
rays ; anal fin with 14 rays, nearer to caudal than to pelvics. Pelvic with g rays, 
pectoral with 13 rays. Lateral scutes 45 in number, the largest being four times as 
deep as broad. Hinder margin of each scute slightly pectinate, anterior margin 
marked with delicate and irregularly arranged vertical striations. 
HoLotypPe. Specimen number 639/59, an imperfect fish in the Museum d’ Histoire 
Naturelle, Geneva, from the Middle Cenomanian of Hakel, Lebanon. 
MATERIAL. Specimens in the B.M.N.H., numbers P.4864, P.g966, P.g967, 
P.9968, P.g970, P.47332, P.47516, all from the Middle Cenomanian of Hakel and 
Hajula, Lebanon, and all prepared by the transfer method. 
DESCRIPTION. Neurocranium. The neurocranium is shown in dorsal view in 
Text-figure 83. The skull-roof is flattened and reaches its widest extent between the 
sphenotics at the hind end of the orbit. The frontals occupy the majority of the 
roof extending back almost to the occiput. The frontals contact each other in a 
straight suture. lLaterally the frontals form the upper border of the orbits and 
extend on to the dorsal surface of the sphenotics. More posteriorly the frontals 
contact the medial edges of the pterotics in a straight suture. The frontal is 
ornamented with raised ridges of bone each set with minute tubercles. The orna- 
mentation of the frontal arises from the centre of ossification above the hind end of 
the orbit. The ridges pass forwards towards the snout region, and also laterally 
above the orbit. Posteriorly directed ridges pass back on to the rear part of the 
frontal above the cranial cavity. Anteriorly the frontals taper most markedly from 
the anterior orbital region and are inserted below the posterior edge of the meseth- 
moid. Posteriorly the frontals overlap the anterior regions of both the parietals 
and the supraoccipital. 
