158 FOSSIL FISHES OF THE ENGLISH CHALK. 
minent bosses or outgrowths. Maxilla with a straight tooth-bearing border, and 
a long supramaxillary bone; teeth conical, in regular series, large and hollow 
on the margin of the jaw, not in sockets. Suboperculum at least half as large as 
the operculum, which is quadrangular but truncated at the postero-superior angle. 
Vertebral centra either ring-shaped or completely ossified. Paired fins without 
fulera, the pectorals with an especially stout preaxial ray. Scales rhombic and 
thick, with a wide overlapped border not produced at the angles, and the peg-and- 
socket articulation feeble or wanting; superficial ganoine nearly smooth; few 
principal flank-seales as deep as broad, the majority broader than deep, and those 
of numerous ventral series at least twice as broad as deep. 
Type Species.—Neorhombolepis excelsus, from the English Chalk. 
Remarks.—This genus differs from Lophiostomus in the less depressed and less 
shortened form of the head and trunk, and in the absence of bony prominences or 
bosses on the external bones. It is known only from the English Chalk and from 
the Wealden formation (Neorhombolepis vuldensis, A. 8. Woodward, Catal. Foss. 
Fishes B. M., pt. iii, 1895, p. 356, pl. viii, fig. 5). 
1. Neorhombolepis excelsus, A. S. Woodward. Plate XXXIV, fig. 1. 
1888. Neorhombolepis excelsus, A. S. Woodward, Proc. Geol. Assoc., vol. x, p. 304, pl. i, fig. 1. 
1895. Neorhombolepis eacelsus, A. S. Woodward, Catal. Foss. Fishes B. M., pt. iii, p. 355, pl. viii, fig. 4. 
T'ype.—Imperfect head with abdominal region; British Museum. 
Specific Characters.—Vhe type species, with skull attaining a length of about 8 
em. Cranial roof ornamented with closely-arranged elongated tubercles and short 
ruge of ganoine; cheek-plates, jaws, and opercular bones more sparsely ornamented. 
Marginal teeth smooth, tumid at base, slender, and slightly meurved at apex ; 
those of maxilla almost as large as those of dentary. Two anterior pectoral fin- 
rays closely ornamented. Scales small and smooth, those of the ventral half of 
the trunk very much elongated, often nearly three times as broad as deep; their 
hinder border either smooth or with from two to four large denticulations. 
Description of Spectmen.—TVhis species is still known only by the type specimen, 
which lacks the snout and the pelvic and paired fins. Its principal characters are 
shown in Pl. XXXIV, figs. 1—1 /f. 
The roof of the skull (figs. 1, 1 @) is very gently arched from side to side, and 
its postorbital region is two thirds as long as broad. Its interorbital region is 
comparatively narrow, and the orbits must have been large. When not flaked 
away, its constituent bones are shown to be ornamented with closely-arranged, 
coarse tubercles of ganoine, which are often fused into short vermiculating ridges. 
The squamosal element (sq.), impressed by the transverse slime-canal, is clearly 
distinguishable, forming each postero-external angle; and the parietals (pa.) 
