. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 253 and the ectopterygoid. The palatine is represented by a narrow strip of bone lying between the lower border of the pterygoid and the maxilla. Hyobranchial apparatus. This too can be seen in specimen P 5594 where it has been a little distorted and crushed during fossilization (Text-fig. 9). The hyomandi- bular is represented hy a thin rod of bone somewhat expanded dorsally to become blade-shaped. It overlies the upper border of the suprapterygoid, but its connection with the quadra
. Bulletin of the British Museum (Natural History), Geology. REVISION OF ACTINOPTERYGIAN AND COELACANTH FISHES 253 and the ectopterygoid. The palatine is represented by a narrow strip of bone lying between the lower border of the pterygoid and the maxilla. Hyobranchial apparatus. This too can be seen in specimen P 5594 where it has been a little distorted and crushed during fossilization (Text-fig. 9). The hyomandi- bular is represented hy a thin rod of bone somewhat expanded dorsally to become blade-shaped. It overlies the upper border of the suprapterygoid, but its connection with the quadrate cannot be seen. No trace of the ceratohyals can be found, although both hypohyals are present. The hypohyal is a stout ossification, with a V-shaped posterior border. This is articulated with a conical almost pointed basihyal. Behind the basihyal are two median basibranchials similar to those described by Watson (1925 : 863) for Elonichthys aitkeni. The first and second branchial arches have long hypobranchials, those of the third and fourth being slightly shorter. The four ceratobranchials are slender and the first two are only partly preserved in this specimen. The fourth ceratobranchial is the most complete and has a small Spt Metpt. Pt Fig. 8. Ectpt Centrolepis aspera Egerton. Left side of palate viewed from its admesial surface, mainly from P 5594. protuberance facing posteriorly near its dorsal extremity. The basihyals, hypohyals and basibranchials are all covered with a shagreen of fine denticles and traces of this also appear on the hypobranchials. It is probable that the whole branchial apparatus was covered with such denticles. Appendicular skeleton. The supracleithrum is very long and extends down from the suprascapular to well beyond the junction of the opercular and subopercular (Text-fig. 5). It is ornamented with coarse tubercles similar to the patterning found on the skull roofing bones. The postcleithrum is also long—about half the length of the s
Size: 2328px × 1074px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
