TILAPIA. 139 



Synopsis of the Species. 



I. Scales cycloid (rarely indistinctly ctenoid). 



A. Gill-rakers 15-27 on lower part of anterior arch. 



1. Anal spines 4 ; pectoral not longer than head, not extending beyond 



origin of anal ; 2 or 3 series of scales on the cheek ; 17—21 gill- 



rakors. 



D. XVI-XVII 11-12 ; A. IV 10-11 ; Sc. 34- 



30 ,, ,. ; mouth extending to between 

 14-15 ' ° 



nostril and eye ; latter 5 times in length 

 of head in adult ; caudal peduncle a little 



longer than deep 1. T. Ituntcri, {U)\r., \>. ]Ad. 



D. XVI-XVII 10-13 ; A. IV 9-10 ; Sc. 30- 

 32 n V-r; ; mouth extending to between 



lo-14 ' ° 



nostril and eye ; latter 4-4£ times in 

 length of head ; caudal peduncle not 



longer than deep 2. T. shimna, Blgr., p. 151. 



D. XVII 11-12 ; A. IV 9 ; Sc. 32 ^ ; mouth 

 extending nearly to below anterior border 

 of eye ; latter 5 to 5£ times in length of 

 head ; caudal peduncle deeper than long . 3. T. nigra, Gtlir., p. 152. 



2. Anal spines 3 (very rarely 4) ; pectoral usually as long as or longer 

 than head, often reaching vertical of origin of anal or beyond. 

 a. Caudal not densely scaled. 



a. Outer teeth small and slender, or unicuspid. 



* Caudal peduncle as long as deep ; 4 series of scales on the cheek ; 

 25 gill-rakers. 

 D. XVII 13 ; A. Ill 11 ; Sc. 33 g ; caudal 



winded 4, T. hafumds, Blgr., p. 153. 



Species with ctenoid scales : — 



13+10=29. T.calUptera. 



13+17=30. T. nigricans. 



14 + 14=28. T. oUgacanthus. 



14+15=29. T.burtoni. 



14+16=30. T. liorii, pallida, nubila, jaappenTieimi. 



14 + 17=31. T. letJirinus, lacrimosa, bayoni, macropliilialnvus. 



15 + 15=30. T.lucidlcB. 

 15 + 16=31. T. simotes. 



15 + 17=32. T.lcirlcii. 



16 4- 1 7 = 33. T. pleurotcenia. 



17 + 17=34. T. dardennii, grandocidis. 



