TILAPIA. 139 



Synopsis of the Species. 



I. Scales cycloid (rarely indistinctly ctenoid). 



A. Gill-rakers ln-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- 

 rakers. 

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



36 rrr^^ ; 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. 7'. //»/i/fW, Gthr., p. 149. 



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

 32 ,^4i : mouth extending to between 



lo-I4 ^ 



nostril and eye ; latter 4-4^ times in 

 length of head ; caudal peduncle not 



longer than deep 2. 7'. s/t/mz/t/, 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. (.^audal not densely scaled. 



«. 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 1| ; caudal 



rounded .4. T. lafuensis, B]g\\, \^. 15Z. 



Species with ctenoid scales : — 



13 + 1 G = 29. T. mlUptera. 

 134- 17= W. T.nicjricans. 



14 + 14=28. T.olvjacanthus. 

 144-15=29. T.hm-toni, 



14+16=:30. T. liorii, imllida, nuhila, pappenhehni. 



144-17 = 31. T. lethrhms, lacrimosa, hayoni, macro i>lttluilmus. 



154-15 = 30. T. Inculke. 



154-16=31. T.simotes. 



154-17=32. T.lirkii. 



16 + 17 = 33. 2\ plcarotania. 



17 + 17 = 31. T. (Janhmni, grfinilornlis. 



