90 
MEMOIBS OF THE QVEEN^LAED MUHEUM. 
Detailed description — Cranium. — The specimen has been subjected to consider- 
able distortion, especially on the right side, the roof of the skull having been obliquely 
crushed down, several of the elements have been displaced, and most of the bones 
are more or less abraded. (Plate XI, fig. 1 ). Tlie supraoccipital is relatively v^ery small, 
and is scarcely raised above the plane of the ])Osterior border. Although the region 
is obscure, the parietals are considered to be small elements not se])arated by the 
supraoccipital, but its anterior small hange apparently underlies them slightly. 
The e])iotic is feebly developed. The cranial roof, in its posterior region, exhibits a 
wide, quadrangular, mi'dian longitudinal depression, hni this has probably been 
much exaggerated by strong [>ressure during fossilisation. It may be noted that a 
deep quadrangular ]>it in the cranial roof is a marked feature of species of Thrissopater, 
a g(uius of the Cretaceous Klopida? from Cretaceous deposits in England. On the 
right side, a ])rominent feature is the large squamosal or ])terotic bone, 110 mm. in 
length. The anterior portion of this bone lias beeti forced upwards. The surface is 
distinctly marked with about eight smooth oblicpie furrows. Only a small posterior 
fragment of the left bone is preserved. In the anterior region of the right squamosal, 
the s]dieuotic or ])ostfrontal forms a laterally projecting ]>rocess (largely obscured on 
the left-hand side), which has an oblicjue trough in its median surface which ])asses 
downwards and backwards. This massiv^e structure evidently formed a remarkable 
feature in the supraorbital region, perhaps as distinctive as that of the giant 
Xiphaciinus, as described by Alban Stewart froju the U])per (Vetaceous of Kansas 
(IhOO). The roof of the skull is so much disrupted in places, however, that 
Flvndersichthys may well have been preyed u])on by one of tlie huge marine reptiles 
such as Kronosa/urus, and it is difficult to inter]>nd precisely its structure. 
Between the orbital region and the occipital border, the roof, mainly comprised 
of frontals, appears to have been parallel-sided. The Avidth at the occipital border 
Avas at least 75 mm., and it Avas apparently quite as Avide between the orbits. 
Anteriorly, the cranium is distinctly narroAAcr. The premaxillye ha\'e been displaced. 
The most anterior element ])resent in tlu^ roof is the unpaired inesethmoid, Avhich is a 
stout bone Avith a median projecting process. On the left side the mesethmoid is in 
co)itact Avith an iuAvardly curAanl process, much abraded, of the maxilla. Eragments 
of the nasals Avath contiguous ])refrontals are present. The A^omer is apparently 
hidden in the cemented material in the upper jiart of the gape, and some of the many 
small teeth here present probably came from it. The bones in the roof of the skull 
in the ])refrontal region are relatiA^ely thick, attaining about 8 mm. 
As the result of long-continued a\ ork on the matrix on the right-hand side, 
poitions of the basioccipital, exoccipital, and ojusthotic are j^artly exj^osed, but the 
area is too obscure to permit of significant description. 
MandUjles.—The massive character of the left mandible is shown on Plate X, 
but its ajiterior ])ortion is incomplete. The right unit has been considerably displaced, 
and the Avhole bone has been thrust some 45 mm. backwards. Its anterior portion 
has been tilted up and noAv lies partly above the incomplete left unit. There is 
