POLTPTEEUS. 



1. POLYPTEEUS. 



Geoffr. Ann. Mus. Paris, i. 1802, p. 57 ; A. Dum. Hist. Poiss. ii. p. 391 (1870) ; 

 Gunth. Cat. Fish. vii. p. 326 (1870) ; Bouleng. Poiss. Bass. Congo, p. 20 

 (1901), and Fish. Nile, p. 2 (1907). 



Body more or less elongate, not serpentiform ; spines of the dorsal 

 fin bearing two or more articulated rays ; ventral fins present ; 

 suboperculum well developed ; teeth small, conical. 



Nile and Tropical Africa. 



Si/nopsis of the Species. 



I. ManJihle projecting slightly beyond the snout ; subojjeroulum much larger 

 than the eye ; pectoral extending as far as first dorsal spine, or beyond ,; 

 11-18 dorsal spines ; 11-15 scales between occiput and lirst dorsal spine. 



A, 60-70 scales along the body, 46-54 round the middle. 

 D. XIV-XVIII ; interorbital region slightly 



convex, 1| (young) to 2| diameters of eye ; 



63-70 scales in longitudinal series .... 1. P. hichir, Geoffr., p. 6. 

 D. XILI-XV ; interorbital region quite flat, 2 

 (young) to 85 diameters of eye ; 60-68 scales 

 in longitudinal series '2. P. lapradu, Stdr., p. 7. 



B. 50-59 scales along the body. 



D. XII-XIV ; interorbital region flat, not more 



than 3 diameters of eye ; usually a small 



azygous shield between the nasals, in the 



adult ; 46-52 scales round middle of body . 3. P. congicus, Blgr., p. 9. 

 D. XI-XIV ; interoibital region flat or slightly 



concave, 2 (young) to 3| diameters of eye ; 



no iizjgous bhield on the snout; 42-46 scales 



round middle of body 4. P. endlichevi, Heck., p. 10. 



II. Both jaws equal in front, or snout projecting beyond mandible ; sub- 

 operculum not much larger, or even smaller than the eye ; 5-11 dorsal 

 spines. 



A. 60-65 scales along the body, 42-46 round the middle ; pectoral widely 

 separated from first dorsal sj)ine ; interorbital region flat or slightly 

 convex, 3 diameters of eye in adult ; 22-26 scales between occiput 

 and first dorsal spine. 

 D. IX-X ; body strongly depressed ; 44-46 scales 



round middle of body 5. P. weeksii, Blgr., p. 11. 



D. X-XI ; body feebly depressed, subcylindrical ; 



42 scales round middle of body Q. P. ornatipinnis, Blgr., p. 12. 



