486 Annals of the South African Museum. 



Dorsal xvi 1 1 ; last, spine longest, -f length of head, middle soft rays 

 produced, nearly f length of head. Pectoral nearly as long as head, 

 extending a little beyond vertical of origin of anal. Ventral reaching 

 slightly beyond origin of anal. Anal iii 10 ; 3rd spine a little shorter 

 than last dorsal spine. Caudal ti*uncate, the angles slightly rounded ; 

 caudal peduncle as long as deep Scales cycloid, 30 T % ; lateral 

 lines f . 



Colour (of preserved specimen) uniform dark olive-brown (almost 

 black), belly greyish, cheeks and lower jaw white ; a rather indistinct 

 dark opercular spot ; vertical fins and ventrals blackish ; tip of dorsal 

 and extremity of caudal lobes yellowish white. 



One specimen, 161 mm. in length, from Umzemutonto River, 

 Transvaal (Major J. Stevenson Hamilton). 



This species is also reported from German East Africa and 

 Mozambique. 



The specimen above dealt with differs slightly in some respects from 

 Dr. Bouleuger's description of T. vorax, but there seems little reason 

 to doubt that it is the same species. 



5. TlLAPIA NATALENSIS, M. Web. 



Chromis niloticus, part., Peters, Arch. f. Nat., 1855, p. 267, and 

 Reise Mossamb., iv, p. 23 (1868) ; Pfeff., Jahrb. H;imb. Wiss. Anst,, x, 

 1893, p. 149, pi. iii, figs. 1-4, and Thierw. O.-Afr., Fische, p. 10, 

 fig. (1896). 



Chrom.is mossambicus, part., Griinth., Cat. Fish., iv, p. 268 (1862). 



Chromis natalensis, M. Web., Zool. Jahrb., Syst. x, 1897, p. 147. 



Tilapia natalensis, Bouleng., Proc. Zool. Soc., 1899, p. 113, Poiss. 

 Bass. Congo, p. 457 (1901), and Freshw. Fish. Afr., iii, p. 157, fig. 103 

 (1915) ; Pellegr., Mem. Soc. Zool. France, xvi, 1904, p. 311. 



Teeth in 3 (young) to 6 series, 50 (young) to 140 in outer series of 

 upper jaw. Depth of body 2^ to 2f times in total length excluding 

 caudal, length of head 2| to 34p times. Head If to about twice as long 

 as broad ; snout rounded, with straight or slightly convex upper 

 profile, as broad as or a little broader than long, T 7 ^ to T % postocular 

 part of head ; eye 3 (young) to 5^ times in length of head, f to ~ inter- 

 orbital width, equal to or a little less or a little greater than preorbital 

 depth ; mouth moderate, f to f width of head, extending to between 

 nostril and eye ; 2 or 3 series of scales on the cheek, width of scaly 

 part not greater than diameter of eye. Gill-rakers short, 16 to 20 on 

 lower part of anterior arch. 



