. Bulletin of the British Museum (Natural History). Zoology . CLUPEOID FISHES OF THE GUI AN AS 159. Fig. 60. Anchoviella guianensis (Eigenmann). Detail of head, from a specimen 6o-o mm , BMNH from remainder by distinct diastema ; tip of lower jaw reaching to first third of snout. Posterior projections of vomer with three to five very small conical teeth and lines of small teeth on palatines, ecto- and endo-pterygoids. Operculum 2-25 times as deep as broad, its posterior margin evenly rounded, its lower margin rising at an angle of about 40 degrees to the horizont
. Bulletin of the British Museum (Natural History). Zoology . CLUPEOID FISHES OF THE GUI AN AS 159. Fig. 60. Anchoviella guianensis (Eigenmann). Detail of head, from a specimen 6o-o mm , BMNH from remainder by distinct diastema ; tip of lower jaw reaching to first third of snout. Posterior projections of vomer with three to five very small conical teeth and lines of small teeth on palatines, ecto- and endo-pterygoids. Operculum 2-25 times as deep as broad, its posterior margin evenly rounded, its lower margin rising at an angle of about 40 degrees to the horizontal; pre-operculum with posterior and ventral margins forming a right-angle, the corner rounded ; exposed portion of sub-operculum long and narrow, 4-5 times as long as deep. Hind edge of gill cover with fleshy border. Least (diagonal) length of cheek (eye rim to postero-ventral angle of 3rd infra-orbital) three-quarters eye diameter. Dorsal surface of head with a median ridge separating the supra-orbital canals, the latter bridged by two bony struts, the posterior oblique but its posterior opening larger than in A. brevirostris. Frontal tips widely separated in the midline posteriorly to expose a pair of fontanelles of variable shape depending on the shape of their lateral boundaries (sigmoid, straight, concave), the fontanelles 1-2-1-6 mm in length and width (about three-quarters width of pupil). Pterotic bulla large, ovoid, almost filling pre-epiotic fossa. Posterior border of gill opening evenly rounded. Isthmus probably silver in life, tapering evenly forward to hind margin of branchiostegal membrane, the latter concealing the exposed portion of urohyal. Branchiostegal membrane narrow, the longest branchiostegal ray equal to snout length. Gillrakers slender, the longest 0-50-0-75 eye diameter and 1-5 times length of corresponding gill filaments ; a series of about 20 spines on each side of gillraker and some scattered but smaller spines down the inner edge of the raker ; po
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