. Bulletin of the British Museum (Natural History), Geology. 308 REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES the ventral edge of the extrascapular, giving off the supratemporal commissure. It continues through the dermopterotic, dermosphenotic and round the infraorbital series as the infraorbital canal. Anteriorly it enters the antorbital where it divides, one half continuing forwards, presumably into the postrostral, while the other unites with the supraorbital canal in the nasal. The supraorbital canal passes upwards through the frontals and unites with the infraorbital canal in the de
. Bulletin of the British Museum (Natural History), Geology. 308 REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES the ventral edge of the extrascapular, giving off the supratemporal commissure. It continues through the dermopterotic, dermosphenotic and round the infraorbital series as the infraorbital canal. Anteriorly it enters the antorbital where it divides, one half continuing forwards, presumably into the postrostral, while the other unites with the supraorbital canal in the nasal. The supraorbital canal passes upwards through the frontals and unites with the infraorbital canal in the dermop- terotic. The preopercular canal is prominent, and passes into the lower jaw as the mandibular canal. Appendicular skeleton. A small supracleithrum articulates the suprascapular to the cleithrum. The cleithrum itself continues downwards to almost the ventral border of the body. Ventrally the cleithrum curves backwards, giving the girdle an unmistakable sigmoidal flexure, not met with in Dapedium. At the level of the subopercular the ossified primary girdle supports four radials ( P 3624). The fin is delicate and made up of approximately twelve 5mm Fig. 43. Tetragonolepis discus Egerton. Ventral ridge scale. From. P3624. The pelvic girdle consists of two small bony rods articulating some seven or eight delicate lepidotrichia. The fin arises near the bottom of the ventral protuberance of the body, in a corresponding position to that in Dapedium. Unpaired fins. The dorsal fin stretches from the dorsal apex of the body almost to the tail, and like the somewhat shorter anal fin has the same number of endo- skeletal supports as lepidotrichia. The caudal fin is not forked and in T. semicincta has eight haemal spines supporting the lower lobe ( ). Axial skeleton. The vertebral column consists of distinct pleuro- and hypocentra. The neural spines are fused to the supporting arches, and in the anterior portion of the body, that is in fr
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