. Bulletin of the British Museum (Natural History), Geology. FISHES FROM THE LEBANON 217 jecting from the lateral and posterior margins of the bone : although this covering flange effectively converts the sensory canal groove into a tube, it is open medially throughout its length. Posteriorly the sensory canal passed to the supratemporal, postero-laterally the preopercular canal left through a large groove, and anteriorly the canal passed to the dermosphenotic. If there was an anastomosis between the temporal and supraorbital canals it can only have lain superficial to the antero-medial part o
. Bulletin of the British Museum (Natural History), Geology. FISHES FROM THE LEBANON 217 jecting from the lateral and posterior margins of the bone : although this covering flange effectively converts the sensory canal groove into a tube, it is open medially throughout its length. Posteriorly the sensory canal passed to the supratemporal, postero-laterally the preopercular canal left through a large groove, and anteriorly the canal passed to the dermosphenotic. If there was an anastomosis between the temporal and supraorbital canals it can only have lain superficial to the antero-medial part of the pterotic : there is no evidence of such an anastomosis on the bones and quite possibly it was not present. There is a small pore in the flange covering the anteriorly directed part of the sensory canal in the pterotic. Immediately behind the posterior, transverse part of the canal there is a large foramen (stv) leading dorso- laterally from the post-temporal fossa which probably transmitted the supratemporal branch of the vagus nerve. Behind this foramen the pterotic bears a long, mem- branous splint which extended back into the body musculature. PrnKT. 3 mm Fig. 5. Gaudryella gaudryi (Pictet & Humbert). Anterior part of skull as preserved in , Hajula, Lebanon. The suffixes ' r ' and '1 ' denote bones of the right and left side, explanation of other abbreviations p. 296. The pterosphenoids (Pts) do not meet the mid-line and each has a notch in its ventral margin, probably marking the passage of the trochlear nerve (IV). There is a large, median orbitosphenoid (Ors ; Fig. 3B) with an anterior process passing for- wards towards the lateral ethmoids below the olfactory nerves, and a stout ventral process extending downwards in front of the optic fenestra. There is a small foramen for the anterior cerebral vein (acv) in the posterior part of the orbitosphenoid. The sclerotic is ossified (scr, Fig. 6), probably in four pieces. (iii) Circumorbital bones. The orbit is
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