78 
ACTINOPTEEYGIT. 
fragmentary on both sides of the fossil. The upper post¬ 
orbital (s.o. 1) is somewhat the smaller, and exhibits a 
series of clefts in its hinder border ; both bear traces of 
the characteristic fine tubercular ornament. The ossified 
sclerotic is seen on the right side. The jaws and teeth 
are imperfect, but best preserved on the left (fig. 1). The 
premaxilla {pmx.') is observed to extend to the front 
border of the orbit; while above the hinder half of the 
comparatively slender maxilla {moo.) there seems to be a 
small supramaxilla Most of the teeth are 
broken and display an internal cavity ; but a few of those 
of the mandible and several of those of the maxilla are 
complete, with the smooth enamelled crown pointed and 
a little curved inwards at the apex. The wide expansion 
of the angle of the preoperculum is observable on the 
left behind the portion of the fossil figured, and the form 
of the large operculum can be dimly perceived on both 
sides. The large and deepl}" imbricating scales, of which 
one from the right side is shown of the natural size in 
fig. 1 6, are externally ornamented with fine tubercles 
tending to arrangement in radiating lines ; and there is 
no appearance either of a mosaic or reticulated structure 
even when this superficial layer of ornament is removed. 
EnmsJ^:illen Coll. 
32345. More imperfect head, the cranium a little crushed down¬ 
wards on the right side. The frontals exhibit the same 
form, thickening, and superficially pitted character as 
before ; their truncated hinder margin is also distinct in 
the same position immediately behind the orbit. The 
anterior thickened and pitted portion of each parietal is 
shown to be about as broad as long, and there are traces 
of the long, narrow squamosal on either side; but the 
occipital region is crushed and obscured. Some of the 
teeth are well shown on the left side. There are also 
characteristic remains of the squamation ; and the right 
supraclavicle is shown to be very long and narrow. 
Purchased.^ 1857. 
P. 157. Imperfect head with cranial roof so fractured as to show 
its thickened character (PI. I. figs. 2, 2 u, 2 h). The 
anterior thickened portion of each parietal {pet.) is at 
least as long as broad, and its postero-lateral angles are 
a little produced backwards. The squamosal {sp) is 
