. Bulletin of the British Museum (Natural History) Zoology. 138 G. J. HOWES & AYANOMIYA FUMIHITO The frontal sensory canal is short and runs diagonally from the anterior fontanelle to the anterior border of the bone where it meets the nasal canal. Owing to the trough-like contour of the anterior part of the frontal the course of the canal is strongly curved. A posterior branch of the canal extends from the posterior fontanelle and follows a diagonal course to the posterolateral border of the bone where it forms a tripartite connection with the infraorbital and temporal canals (lfc, Fig. 2A
. Bulletin of the British Museum (Natural History) Zoology. 138 G. J. HOWES & AYANOMIYA FUMIHITO The frontal sensory canal is short and runs diagonally from the anterior fontanelle to the anterior border of the bone where it meets the nasal canal. Owing to the trough-like contour of the anterior part of the frontal the course of the canal is strongly curved. A posterior branch of the canal extends from the posterior fontanelle and follows a diagonal course to the posterolateral border of the bone where it forms a tripartite connection with the infraorbital and temporal canals (lfc, Fig. 2A). The sphenotic (sp., Fig. 3B) borders the posterolateral margin of the frontal but anteriorly is separated by that bone from the lateral ethmoid. Ventrally, the sphenotic contains the anterior part of the hyomandibular fossa. The cranial surface of the pterotic is concave, its raised lateral margin bearing the sensory canal. Posteriorly the border of the pterotic is indented where it meets the posttemporosupra- cleithrum; medially it contacts the supra- and epioccipitals; its ventral surface contains two long fossae, the upper for the origin of the adductor mandibulae muscle, the lower for the articulation of the hyomandibular (dmf hyf, Figs 3,5). The supraoccipital is a large anteriorly sloping bone that bears a shallow medial crest is continuous with that of the frontal; the semicircular canal tube is raised well above the bone's surface and runs posterolaterally to join the similarly elevated canal tube of the square-shaped epioccipital (epo, Figs 3B, 5). The exoccipital contributes to the dorsal surface of the cranium between the supra- and epioccipitals; posteriorly it is perforated by an extensive vagus foramen and posteromedially rises to border the supraoccipital (Fig. 6A). Its ventrolateral face is perforated by the glossopharyngeal foramen (fg, Fig. 3B). The basioccipital is short with a slight median keel (bo. Figs 3, 5); its exposed lateral surface is joined to th
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