T1LAPIA. 



247 



78. TILAPIA POLYACANTHUS. 

 Bouleng. Ann. Mus. Congo, Zool. i. p. 124, pi. xlv. fig. 6 (1899), and Poiss. Bass. 

 Congo, p. 471 (1901) ; Pellegr. Mem. Soc. Zool. France, xvi. 1904, p. 326. 



Depth of body nearly equal to length of head, 3 to 3i times in total 

 length. Occiput somewhat humped in the male. Snout with straight 

 or convex upper profile, as long as postocular part of head ; eye 3§ to 4 

 times in length of head, equal to interorbital width and to praeorbital 

 depth ; mouth § to |- width of head, extending to between nostril and 

 eye ; upper lip much developed on the side ; teeth in 5 or 6 series, 

 outer rather large, 44 to 50 in upper jaw ; 3 or 4 series of scales on 

 the cheek, width of scaly part equal to diameter of eye. Gill-rakers 

 short, 9 or 10 on lower part of anterior arch. Dorsal XVIII-X1X 8-9 ; 

 spines subequal from the fifth or sixth, ^ to f length of head ; longest 



Fig. 165. 



Tilapia poly acanthus. 

 Type (A.M. C). f. 



soft rays -f to i length of head. Anal III 7-8 ; third spine a little 

 longer than longest dorsal. Pectoral § to f length of head, not extend- 

 ing to vertical of origin of anal. Ventral not reaching vent. Caudal 

 rounded. Caudal peduncle as long as deep or a little longer than deep. 



^-4 • ^ 24 



Scales denticulate, 32-34 -jt= ; lateral lines ~§zy>- Dark olive-brown ; 

 ^ill-cover, dorsal, anal, and caudal fins edged with blackish; ventrals 

 blackish. 



Total length 80 millim. 



Lake Mweru. — Type in Congo Museum, Tervueren. 

 1-3. Ad. & yg. Pweto, L. Mweru. Dr. L. Stappers (0.). 



79. TILAPIA PLEUROT.ENIA. 



Bouleng. Ann. & Mag. N. H. (7) vii. 1901, p. 4, Poiss. Bass. Congo, p. 474 

 (1901). and Tr. Zool. Soc. xvi. 1901, p. 157, pi. xviii. fig. 4 ; Pellegr. Mem. 

 Soc. Zool. France, xvi. 1904, p. 333. 



