1899.] STRIAIS- FISHES OF THE FAMILY CICIILID^. 127 



scales on the opercle. Grill-rakers very short, 8 on lower part of 

 anterior arch. Dorsal XVI 12-13 ; last spine longest, i length 

 of head. Pectoral pointed, a little longer than the head, extending 

 as far as origin of anal. Ventral not reaching vent. Anal III 

 9-10 ; third spine as long as middle dorsals. Caudal rounded. 

 Caudal peduncle not longer than deep. Scales cycloid, 80-32 

 jg^-j^ ; lat. 1. j^r[|. Body without distinct markings ; snout and a 

 spot on the opercle blackish ; dorsal fin with blackish spots and 

 oblique bars. 



Total length 220 miliim. 



Upper Shire River. 



37. TiLAPIA. AFFINIS. 



Tilapia affinis, A. Dum. Arch. Mus. x. 1859, p. 255. 



Ohromis affinls, Eochebr. Act. Soc. Linn. Bord. vi. 1883, p. 131. 



Chromis miretis, Steind. Verh. zool.-bot. Ges. Wien, xiv. 1864, 

 p. 229, pi. viii. fig. 5. 



Teeth small, in 3 or 4 regular series in both jaws. Depth of 

 body 21- to 2| in total length, length of head 3. Snout with 

 straight upper pi^ofile, 1^ to 1^ diameter of eye, which is contained 

 4 times in length of head, and li to li- in interorbital width ; 

 mouth nearly | width of head, extending to below anterior border 

 of eye ; 3 series of scales on the cheek ; large scales on the opercle. 

 Gill-rakers short, 8 or 9 on lower part of anterior arch. Dorsal 

 XV 11-12 ; last spine longest, -i- length of head, nearly i longest 

 soft rays. Pectoral pointed, 1^ length of head, extending to 

 origin of anal. Ventral reaching origin of anal. Anal III 8-10 ; 

 third spine a little shorter than last dorsal. Caudal rounded. 

 Caudal peduncle slightly deeper than long. Scales cycloid, 

 32 ^j-^^ ; lat. 1. j^. Olive, a black opercular spot ; soft dorsal with 

 blackish spots more or less confluent into oblique streaks. 



Total length 170 miliim. 



Senegal and Niger. 



38. TlIiAPIA BUBTOlSri. 



Chromis burtoni, Giinth. Proc. Zool. Soc. 1893, p. 631, pi. Iviii. 

 fig.C. 



Tilapia biirtoni, Bouleng. Tr. Zool. Soc, xv. 1898, p. 5. 



Teeth in 5 closely-set series, outer moderately large, inner very 

 minute. Depth of body 2| in total length, length of head 2i. 

 Snout with slightij^ concaA'e upper profile, Ij diameter of eye, 

 which is contained 4 times in length of head and equals inter- 

 orbital width ; mouth rather large, nearly | width of head, 

 extending to below anterior border of eye ; 4 series of scales on 

 the cheek ; large scales on the opercle. Gill-rakers short, 10 on 

 lower part of anterior arch. Dorsal XIV 11 ; spines equal from 

 the 10th, I length of head, | longest soft rays. Pectoral 4 length 

 of head, extending as far as origin of anal. Ventral prolonged in 



