376 On nexo Freshwater Fishes from Portuguese Guinea. 



Pectoral spine as long as or slightly longer than head, 

 strongly serrated on both sides. Ventral reaching origin of 

 anal or a little beyond. Caudal deeply notched, upper lobe 

 the longer. Caudal peduncle as long as deep or a little 

 deeper than long. Dark brown above and below, head, body, 

 and dorsal fins with numerous round black spots. Young 

 paler brown, with larger and fewer black spots ; fins whitish, 

 with large black spots forming cross-bars on the anal and 

 caudal. 



Total length 235 mm. 



Numerous specimens from the Geba and Culufi Rivers. 



This species, which may be placed near S. nigrita, C. & V., 

 and melanopterxis, Blgr., is very distinct from any previously 

 described. 



Tilapia ansorgii. 



Depth o£ body twice in total length, length of head 3 times. 

 Head If times as long as broad, upper profile slightly con- 

 cave ; snout as long as broad. If times as long as eye in 

 adult, as long as eye in young ; eye 3 (young) to 4 times in 

 length of head, 1 to If times in interorbital width, equal to 

 depth of prseorbital ; mouth extending to between nostril and 

 eye, extremity of maxillary exposed ; outer teeth in both jaws 

 large, obtusely bilobed, 20 (young) to 38 in upper jaw, 

 followed after a wide interspace by a few minute tricuspid 

 teeth arranged in 2 or 3 transverse series ; 5 or 6 series of 

 scales on the cheek, the vertical diameter of the scaly part 

 below the eye equal to diameter of latter. Gill-rakers rather 

 short, the larger anvil-shaped, 11 or 12 on lower part of 

 anterior arch. Dorsal XIV-XV 14-15 ; spines increasing in 

 length to the last, which measures ^ to § length of head ; 

 longest soft ray | to | length of head. Anal III 10-U ; 

 third spine longest, stronger but shorter than longest dorsal. 

 Pectoral a little shorter than head, not reaching vertical of 

 origin of anal. Ventral produced into a long filament, 

 reaching origin of anal or beyond. Caudal rounded, scaly all 

 over in the adult. Caudal peduncle deeper than long. Scales 

 not or but very feebly denticulate, 30-32 ^^^^ ; lat. 1. gf ' 

 Grey or brown, with seven or eight broad black vertical bars 

 descending to the mid-ventral line, the first passing through 

 the eye, the last on the caudal peduncle ; pectoral greyish, 

 other fins blackish. 



Total length 210 mm. 



Several specimens from the Geba and Culufi Rivers. 



