GOBIIDAE Acentrogobius caninus, NSMT-P 66089, 6.0 cm SL Acentrogobius caninus (Valenciennes, 1837) Tropical sand goby D VI - I, 9; A I, 9; P1 18; LR 26 - 27; PDS 16. Body moderately elongate, compressed posteriorly. Head slightly compressed; jaws subequal; gill opening not extending anteriorly to a vertical through preopercular margin; single or some enlarged caninoid teeth on each side of lower jaw. Pelvic fins united medially. Scales ctenoid, excluding those on nape, pectoral base and breast cycloid; no scales on cheek, operculum often scaled. Sensory canals and pores present on head; longitudinal pattern of sensory-papillae rows on cheek, some rows multiple; aggregation of sensory papillae just behind chin. Color: large ovoid black spot just above dorsalmost of gill opening; 4 midlateral dusky spots on body. Size: 13.0 cm. Distribution: Indo-West Pacific. Remarks: found in tidal estuaries with sandy-mud bottom.