TILAPIA. 



191 



broad or a little broader than long, as long as postorbital part of head; 

 eye 3 (young) to 5 times in length of head, 1 (young) to 2j times in 

 interorbital width, less than preeorbital depth in adult ; mouth moderate, 

 -f to -| width of head, extending to between nostril and eye; teeth in 3 

 (young) to 5 more or less regular series, outer lai'gest, 30 (young) to 60 

 in upper jaw, and separated from the others by a rather wide interspace ; 

 3 or 4 series of scales on the cheek, width of scaly part greater than 

 diameter of eye in adult. Gill-rakers short, 8 to 12 on lower part of 



Fig. 123. 





Tilapia melanojileura. 

 Type of T. latifrons (Tr. Z. S. 1906). 



anterior arch. Dorsal XV-XVI 10-14; last spine longest, § to § 

 length of head ; middle soft rays more or less produced in adult, usually 

 as long as or a little longer than head. Anal III 9-11 ; third spine 

 usually shorter than the longest dorsal. Pectoral 1 to \\ times as long 

 as head, often extending nearly to vertical of origin of anal. Ventral 

 usually reaching vent or anal. Caudal truncate or feebly emarginate. 

 Caudal peduncle deeper than long. Scales cycloid or very feebly 

 denticulate, 29-32 =~ ; lateral lines j^. Olive-brown, with or with- 

 out 4 to 6 very indistinct darker bar6 ; a black opercular spot ; dorsal 

 fin with blackish oblique streaks, or grey or blackish, with or without 



