. Bulletin of the British Museum (Natural History) Zoology. 118 IAN HARRISON & GORDON HOWES pb1. eb1 Fig. 4 Upper gill-arch elements of Mugil cephalus in A, dorsal and B, medial views. For clarity, in A, the toothplates are shown in outline only. Specimen PA 271186T, mm SL. Scale = mm. ultimate structure is a small protruberance, the original long fold remaining as its fleshy base. Between 30-44 mm SL these three taxa also develop a secondary valve or protruberance from the ventral part of the posterior VP. The sulcus is present in the earliest available stages as a narrow and sha
. Bulletin of the British Museum (Natural History) Zoology. 118 IAN HARRISON & GORDON HOWES pb1. eb1 Fig. 4 Upper gill-arch elements of Mugil cephalus in A, dorsal and B, medial views. For clarity, in A, the toothplates are shown in outline only. Specimen PA 271186T, mm SL. Scale = mm. ultimate structure is a small protruberance, the original long fold remaining as its fleshy base. Between 30-44 mm SL these three taxa also develop a secondary valve or protruberance from the ventral part of the posterior VP. The sulcus is present in the earliest available stages as a narrow and shallow groove. The principal changes in its morphology occur between ca. 23-40 mm SL and involve increases in breadth and depth. The most significant development is the opening and widening of the dorsoposterior aperture beneath the 4th cpibranchial (Fig. 1 A). Skeletal elements: Discounting intergeneric and interspecific variability in the adult form, the basic ontogeny of the upper gill-arch elements follows the same pattern in all taxa studied. At the earliest available stage ( mm SL Liza ramada, Fig. 9A), the toothplates are triangular and meet one another along their respective straight, posterior and anterior borders, The 4th toothplate is shorter than the 3rd and both bear a few proximal-type teeth mostly along their outer margins. Along its posterior border the 3rd pharyngobranchial bears two small cartilaginous processes; a lateral one articulating with the 3rd cpibranchial and a medial one articulating with the cartilaginous 4th pharyngobranchial which, in turn, articu- lates with the 4th epibranchial. The 2nd pharyngobranchial bears distinct proximal teeth. In a 14 mm SL Liza saliens (Fig. 9B), the situation is similar but the articular processes have extended and a thin laminate keel has developed from the base of the lateral process to extend anteriorly. The base of the 4th epibranchial has expanded to overlap the 4th pharyngobranchial. The teeth are of the proxi
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