TILAPIA. 



217 



5]. TILAPIA BURTONI. 

 Chromis burtord, Guiith. Proc. Zool. Soc. 1893, p. 631, pi. Iviii. fig. C. 

 Tilapia burtoni, Bouleng. Tr. Zool. Soc. xv. 1898, p. .5, Proc. Zool. Soc. 1899, 



p. 127, and Poiss. Bass. Congo, p. 460 (1901) ; Pellegr. Mem. Soc. Zool. 



France, xvi. 1904, p. 320. 



Depth of body 2^ to 21 times in total length, length of head 2f to 

 S} times. Head 2 to 2| times as long as broad; snout with straight 

 or slightly concave upper profile, as long as or a little shorter than 



Fig. 140. 





Tilapia burtoni. 

 Kitutu. 



broad, much shorter than postocular part of head, 1 to 1^ times as long 

 as eye, which is 3^ (young) to 4 times in length of head, equals inter- 

 orbital width, and exceeds least depth of praeorbital ; mouth rather 

 large, f to f width of head, extending to below anterior border of eye 

 or a little beyond ; maxillary exposed ; teeth small, in 4 to 6 series 

 close together, 50 (young) to 70 in outer series of upper jaw ; 3 to 5 

 series of scales on the cheek. Gill-rakers short, 9 or 10 on lower part 

 of anterior arch. Dorsal XIV-XV 9-11; spines increasing in length 

 to the tenth or last, which measures 5^ to ^ length of head ; longest soft 

 rays about f length of head. Anal III 8-9 ; third spine as long as or 

 a little shorter than longest dorsal. Pectoral | to f length of head, 

 reaching or not vertical of origin of anal. Ventral somewhat produced, 

 extending to origin of anal or beyond. Caudal rounded or rounded- 

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



o_o]^ . I 8-'^l 



Scales more or less distinctly denticulate, 28-31 -jf ; lateral lines -^rJT;' 



