. Bulletin of the British Museum (Natural History). Zoology . 162 P. J. P. WHITEHEAD. Fig. 6i. Anchoviella cayennensis (Puyo). From Hildebrand & Carvalho 1948 (as A. victoriae). Operculum about twice as deep as broad, its lower margin rising at an angle of about 60 degrees to the horizontal; pre-operculum with its posterior and ventral margins forming an approximate right angle ; exposed portion of sub-operculum long and narrow. Least (diagonal) length of cheek (eye rim to postero-ventral angle of 3rd infra-orbital) three-quarters eye diameter. Dorsal surface of head with medi
. Bulletin of the British Museum (Natural History). Zoology . 162 P. J. P. WHITEHEAD. Fig. 6i. Anchoviella cayennensis (Puyo). From Hildebrand & Carvalho 1948 (as A. victoriae). Operculum about twice as deep as broad, its lower margin rising at an angle of about 60 degrees to the horizontal; pre-operculum with its posterior and ventral margins forming an approximate right angle ; exposed portion of sub-operculum long and narrow. Least (diagonal) length of cheek (eye rim to postero-ventral angle of 3rd infra-orbital) three-quarters eye diameter. Dorsal surface of head with median ridge separating the supra-orbital canals, the latter bridged by two bony struts, the posterior oblique and its posterior opening as in A. guianensis (cf. A. brevirostris, where it is minute). Frontal tips not widely separated in the midline posteriorly (Figure 62b), a pair of fontanelles exposed with convex lateral borders, the fontanelles i-i mm long and together 1-5 mm in width. Pterotic bulla incon- spicuous, not bulging out into pre-epiotic fossa. Posterior border of gill opening evenly rounded. Isthmus silver, tapering evenly forward to hind margin of branchiostegal membrane, the latter concealing exposed portion of urohyal. Branchiostegal membrane narrow, the longest branchiostegal ray just over snout length. Gillrakers slender, the longest half eye diameter and 1-33 times length of corresponding gill filaments ; a series of about 15 spines on each side of gillraker and minute scattered spines down inner edge of raker ; posterior face of 3rd epibranchial with seven small triangular gillrakers. Pseudo- branch present, invested with thin skin, its length three-quarters of eye diameter, with about 20 filaments. Dorsal origin equidistant between anterior eye border and base of caudal; base of fin invested in low scaly sheath ; longest rays just reaching to tip of last branched ray when fin depressed. Pectoral fin tips failing to reach pelvic base by almost one eye diamete
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