. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 251 of the orbit and its posterior edge. The first member of the pair passes back from the rostralo-premaxillary with its ventral edge in contact with the maxilla. Posteriorly it abuts the suborbital and the other infraorbital. The second infraorbital passes upwards articulating with the anterior edges of the two suborbitals. Dorsally it adjoins a small fragment of bone (see 38123) which represents part of the dermo- sphenotic. The infraorbital sensory canal can be traced from the der
. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 251 of the orbit and its posterior edge. The first member of the pair passes back from the rostralo-premaxillary with its ventral edge in contact with the maxilla. Posteriorly it abuts the suborbital and the other infraorbital. The second infraorbital passes upwards articulating with the anterior edges of the two suborbitals. Dorsally it adjoins a small fragment of bone (see 38123) which represents part of the dermo- sphenotic. The infraorbital sensory canal can be traced from the dermopterotic, into the dermosphenotic, where it turns sharply downwards and passes round through the infraorbitals into the rostralo-premaxillary. The two suborbitals are largish bones which fit in between the infraorbitals and the concave anterior edge of the maxilla and preopercular. The maxilla and preopercular are typically Palaeoniscid in structure. The maxilla is much broadened posteriorly and is long and slender anteriorly. The oral border of the maxilla bears teeth along its entire length, the teeth being in two series, an outermost series of small, numerous, sharply pointed. 5 mm Fig. 6. Centrolepis aspera Egerton. Nasal and postrostral bones of the left side showing internal nares. From P 5594. teeth, and an inner series of much larger, less numerous and slightly curved teeth. The preopercular sensory canal runs along the posterior border of the preopercular, and the supramaxillary canal is represented by a distinct groove which passes from the antero-dorsal region of the preopercular down into the maxilla (he. in Text-fig. 5). From the angle of the opercular bones the suspensorium is very oblique, with the opercular lying almost horizontal above the preopercular. The opercular is almost twice as long as it is broad and is a little larger than the subopercular. The sub- opercular is more vertical in position and as broad as it is deep. The number of branchioste
Size: 1610px × 1552px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
