. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 323 distance. However, a further portion of the supraorbital canal can be traced in the postero-dorsal corner of the mesethmoid. Traces of the preopercular canal were found near the anterior border of that bone, and further evidence of it can be seen in the small separate preopercular plate above. The infraorbital canal is continuous with the cephalic division of the main lateral line, and curves down through the dermopterotic. Its further passage is again obscured by the poor state o
. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 323 distance. However, a further portion of the supraorbital canal can be traced in the postero-dorsal corner of the mesethmoid. Traces of the preopercular canal were found near the anterior border of that bone, and further evidence of it can be seen in the small separate preopercular plate above. The infraorbital canal is continuous with the cephalic division of the main lateral line, and curves down through the dermopterotic. Its further passage is again obscured by the poor state of preservation in that area. The cephalic division of the main lateral line passes upwards on to the ventro-posterior margin of the parietal, where it gives off a well developed supratemporal commissure. The presence of this cross commissure on the hind margin of the parietal suggests that the Sp Den. Ang ( 5 mm t Fig. 52. Eomesodon liassicus (Egerton). Lower jaw and quadrate. From P 1336. parietal represents two bones, the parietal and the extrascapular. Posterior to the supratemporal commissure, the main lateral line turns downwards into the antero-dorsal corner of the supracleithrum passing diagonally backwards through this bone and then out on to the body scales as the main lateral line. The dorsal lateral line is a narrower canal, situated more superficially. It begins in the centre of the dorsal portion of the supracleithrum where it communicates with the main lateral line. It passes upwards and backwards to the dorsal edge of the supracleithrum, and then continues into the body scales, running along parallel with the dorsal margin of the body. It can be traced back almost to the dorsal fin. The main lateral line is well developed and its structure can be seen on P $i2j. The canal appears to open to the surface between each scale, there being a distinct gap between the end of the canal on one scale and the recommencement of it on the succeeding scale. An
Size: 2347px × 1065px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
