HOPLOrTERYX. 17 



foramina piercing- tlie l)o\Hi(liiif>- ridge on each side. Muscles covered l)y scales (B. M. 

 no. 49043) occni)ied the greater part of the trough just descril)ed, but the small 

 anterior triangular portion must have been a slime-cavity. The frontal bones (PI. 

 Ill, fig. 2, /r.) extend from the hinder border of the orbit to the front margin of 

 the prefrontal or ectethmoid, where they meet the mesethmoid (eth.) in a 

 jagged suture. They form a slight supraorbital flange on each side, marked with a 

 coarse, tubercular ornament at the border. Internal to this flange and external to 

 the great ridge already described, they are transversely ridged to produce three 

 pairs of lateral slime-cavities, which are connected with each other by foramina 

 piercing the bounding walls. The largest or anterior cavity (n, iii) is again 

 bridged by a thin spicule of bone at the anterior end of the frontal, as shown 

 in the restoration (Text-fig. ou). This delicate bridge is lacking in most 

 fossils, as in the original of PL III, fig. 2 ; but it is indicated in nos. 49038, P. 

 1948 b, and other specimens in the British Museum. The mesethmoid (etJi.) is as long- 

 as broad, entirely in advance of the frontals, and impressed in front with a deep 

 groove for the reception of the ascending processes of the premaxilla>. The pre- 

 frontal or ectethmoid is very deep and narrow. When Avell preserved, all the 

 sharp ridges of the cranial roof, except the supraoccipital, are observed to be 

 ornamented on the edge with a row of tubercles ; and similar tubercles are seen on 

 the lateral borders of the mesethmoid. 



The mandibular suspensorium is nearly vertical, the gape of the mouth extend- 

 ing just behind the eye. The hyomandibular (Pis. Ill, VII, fig. 1, Jivi.) is deep 

 and narrow, and its outer face l^ears a large, thin laminar ridge bordering the 

 anterior edge of the preoperc\ilum, as in Berijx. A small symplectic bone {sij.) 

 is exposed on the outer face of the suspensorium, and fits in a notch of the 

 quadrate {qn.). The palato-pterygoid arcade is partly shown in fig. 1 of Pis. Ill 

 and VII, but is nnicli obscured in both and incomplete at its upper margin in the 

 latter, where the entopterygoid is wanting. It evidently resembles the corresponding- 

 arcade of lievy.e, but the inner face of the deep laminar palatine (j'Z.) bears a more 

 extended patch of minute teeth, which is continued on the anterior end of the 

 ectopterygoid (fcpf.). The premaxilla {pmx.) completely excludes the maxilla from 

 the upper border of the mouth on each side, but only a very narrow margin is 

 exposed when the maxilla rests naturally upon it. The straight oral border of the 

 bone is widened and bears a broad band of minute, blunt teeth throughout its length, 

 well seen from the inner aspect in PL III, fig. 3. Its overlapped middle portion is 

 produced upwards into a small, thin wing (fig. 1, 'pmx., fig. 3) ; while its anterior 

 end is sharply upturned in a forked process. The maxilla {m,i\) is almost or quite 

 smooth, w4th a large, sharply upturned process in front, and a small triangular 

 expansion l)ehind. Its anterior process bears at the upper extremity a convex 

 facette for articulation with the palatine ; and the hinder half of the upper 

 border of the l)one is overlap})ed by two su})rama\ill;¥. Of these the postei'ior 



3 



