MEMOIliH Ob' THE QUEENSLAND MUSEUM, 
:y2 
Alaxillce. — The left maxilla is very incomplete and much abraded. Anteriorly 
it shows a j^rominent, inwardly-directed process, apparently terminating at its junction 
with the unpaired mesethmoid. The region above the maxilla, overlying the palato- 
quadratc bar, is so abraded that it cannot be stated whether supjdementary or supra- 
maxillary bones were j)resent. On the right side, exposed under deep matrix, the 
maxilla has been forced downwards and inwards on to the margin of the mandible. 
The length, as exposed in the matrix, is fully 188 mm., and the depth is approximately 
25 mm. The anterior ]K>rtion gives evidence of a pronounced inward and upward curve. 
The bone is gently curved througliout its length, and is somewhat convex on its lateral 
surface \n transverse section. The depth is fairly uniform, but the bone was evidently 
thicker anteriorly. On the superior border there is a small elongated channel, which 
may have been associated with the bases of supramaxillary bones. Unfortunately 
the matrix on the oral border is extrejnely hard, and the bone cannot be further 
exposed. Thei'e is evidence of a close-set series of tiny conical teeth, which may be 
seen in the matrix. Within the anterior portion of the gape, the matrix is very hard, 
being evidently composed of the cemented detritus of disrupted bone, but numerous 
remains of vilUform or minute conical teeth are more or less exposed. 
QmdrateaiidSi/mphclic. — These two conjoined bones form a massive triangular 
])late. At the condyle the quadrate is no less than 20 mm. thick, thus forming a 
powerful hinge for the mandible. The right quadi-ate has been forced backwards 
and inwards, but its condyle is still in the articulating surface of the mandible. The 
condyle, as shown on the left side, has a pronounced inwardly-directed process, 
a])j)arently as in Oligopleurm vectensis, as described by Smith Woodw'ard (1890, p. 
347.). The symplectic is closely associated with the quadrate on its supero-posterior 
border. The ])osterior edge of tlie symplectic passes beneath the lower portion of the 
hyomandibular. which partly overlaps it. 
Palailne, — Articulating obliquely with the anterior border of the quadrate, 
and in the same lateral plane, is an elongated, curved bone, much abraded, which 
evidently represents the palatine with a jderygoid element closely adpressed. It 
terminates in the ethmoid region in juxtaposition with the maxilla. It may be 
mentioned tiiat in Arapaiwa, according to Ridewnod (1004. p. 73), the cctopterygoid 
is fused with the ]mlatine. Inside this palato-pterygoid arch and below' the suborbital 
]date a small portion of a meso])terygoid bone is exposed. 
(Jrbital regm?!..— Immediately above the quackate and the palato-pterygo- 
quadrate arch, a massive plate of bone extends from the hyomandibular to the 
])rcorbital region. The natural surfaces are somewhat abraded, but it appears to 
consist of a single bone, extending to the lower l)order of the orbit. This })latc is verv 
thick and convex near the quatkate, but it shelves inw'ards in consonance with the 
narrow ing of the cranium in its upper })ortion. The diameter of the orbit appears to 
have been about 40 mm. The actual region is partly filled with cemented detritus. 
