16 
both on the front part of the maxilla {nix.) and on the hinder part of the 
dentary {md.). The opercular apparatus {op.) is narrow, and coarsely 
ornamented with tubercles. Owing to fractures, the line of suture between 
the operculum and suboperculum (sop.) is uncertain; but it seems to be low 
down, as if the operculum were very deep and narrow, not relatively small. 
The usual broad branehiostegal rays {hr.) are seen below. 
Vertebral Axis. — The neural and lisemal arches of the vertebral axis 
are sufficiently well calcified to be preserved, and many of them are exposed. 
In the abdominal region, the long and slender neural spines {n.s.) are 
separate from their short supporting arches ; while the haemal elements are 
merely paired bosses of calcified cartilage, which are slightly displaced in the 
fossil so as to be shown one series above the other. 
Appendicular Skeleton. — Traces of the pectoral arch are preserved, 
the supraclavicle being deep and narrow, and meeting the tapering upper end 
of the clavicle, where there seems to be a small postclavicular plate. The 
large infraclavicles {i.cl.) arc conspicuous. Some obscure remnants of closely 
articulated rays appear to represent the pectoral fin {pet.). All the rays of 
the fins are stout and rather closely articulated to the base, while their outer 
face (when seen as preserved in the dorsal fin) is ornamented with fine 
longitudinal flutings. Remains of the anterior edge of both pelvic fins {plv.) 
occur, with indications of a fringe of small fulcra. Only the middle portions 
of the dorsal {d.) and anal {an.) are seen in the type specimen, the former 
being in an unusually remote position. The low, fringing, posterior extension 
of the dorsal fin is preserved in No. c. 
Squamation. — The scales are shown in the type specimen in all 
conditions, sometimes from the outer or inner face, often fractured, sometimes 
as mere impressions. Their external face is better seen in the fragment 
No. b. They are relatively small and thick, in regular order over the whole 
of the trunk, and ornamented with coarse ridges, which often exhibit a fine 
secondary longitudinal striation. The ornamental ridges apparently do not 
produce serrations at the hinder border of the scales. As shown by an 
impression of the outer face (PI. Ill, Fig. 3), the principal flank-scales in 
the anterior part of the abdominal region are twice as deep as broad, and 
their overlapped border is narrow. Their ornamental ridges, which often 
bifurcate in front, are only slightly oblique. As shown in the middle of the 
abdominal region in the type specimen, the scales are united by a large 
