. Bulletin of the British Museum (Natural History) Zoology. PHARYNGOBRANCHIAL ORGAN OF MUGILID FISHES swb ns3 rdd 117. gt os pfb pbo tv Fig. 3 Liza waigiensis (BMNH 25: 3649-73, 97 mm SL). Dissection of head to show unique configuration of retractor dorsalis muscle; the right half of the PBO has been cut away. gill-rakers similar to those on the 1st epibranchial, and lies well anterior to the denticulate area of the PBO. The 2nd and 3rd ceratobranchials have shorter and closer-set gill-rakers and lie anterior to the PBO, although the posterior rakers of the 3rd surround part of the sul
. Bulletin of the British Museum (Natural History) Zoology. PHARYNGOBRANCHIAL ORGAN OF MUGILID FISHES swb ns3 rdd 117. gt os pfb pbo tv Fig. 3 Liza waigiensis (BMNH 25: 3649-73, 97 mm SL). Dissection of head to show unique configuration of retractor dorsalis muscle; the right half of the PBO has been cut away. gill-rakers similar to those on the 1st epibranchial, and lies well anterior to the denticulate area of the PBO. The 2nd and 3rd ceratobranchials have shorter and closer-set gill-rakers and lie anterior to the PBO, although the posterior rakers of the 3rd surround part of the sulcus border. The 4th cerato- branchial surrounds the lateral face of the denticulate area, and the 5th, which is an expanded lamniform bone, cups the posteromedial region of the organ. The medial border of the 5th ceratobranchial bears proximal-type teeth which are distinct in the juveniles but remain relatively small, if not vestigial, in adults (p. 119). The gill-rakers on the inner surfaces of the ceratobranchials are spaced and orientated in such a way that when drawn together, they intermesh with the outer rakers of the next arch. Since the gill-rakers of the 4th and 5th ceratobranchials enclose the denticulate cushion, they intermesh with the distal teeth of the organ. Several types of gill-raker can be recognised in mugilids (Ingham, 1952). The cartilaginous tips of the 2nd-4th ceratobranchials, which articulate with those on the epibranchials, are drawn out into scytheshaped blades; from these run the rows of gill filaments which pass away from and above the epibranchials and are supported only by their transverse membrane (Fig. 7). DEVELOPMENT The following ontogenetic observations apply to Mugil cephalus, Liza saliens, L. aurata, L. ramada and Chelon labrosus from the Mediterranean. External morphology: The PBO is at least moderately developed in specimens of ca. 11 mm SL. Liza spp of this size have folds on the anterior part of the lateral wall which are the precursor
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