120 -SIB. G. A. BOULENGEB OS THE AFEICAX AND [Feb. 7, 



Haligenes tristrami, Giinth. Proc. Zool. Soc. 1859, p. 471, pi. ix. 

 fig.B. 



Chromis tristrami, part., Griinth. Cat. ir. p. 269 (1862). 



Sarotherodon (?) :ilUi, Giiuth. Cat. iv. p. 274. 



Chromis andi-ece, Giinth. Proc. Zool. Soc. 1864, p. 492; Lortet, 

 Ann. Mus. Lvon, iii. 1SS3. p. 142, pi. viii. fig. 3 ; Tristram, Faun. 

 Palest, pi. x\-]i. fig. 1 (1884). 



Chromis niloiicus, part., Gervais, Zool. Pal. Gen. p. 205. pi. xlv. 

 fig. 3 (1869), and Journ. Zool. iii. 1874, p. 455. 



Chromis mossamhicus, part., Steind. Sitzb. Ak. Wien, Ix. i. 1870, 

 p. 23. 



Chromis zillii, Sauvage, Bull. Soc. Philom. (7) i. 1877, p. 163 ; 

 EoUand, Eev. Scientif. (4) ii. 1894, p. 418. fig. 



Chromis tristrami, Giinth. Proc. Zool. Soc. 1S96, p. 218. 



Tilapia tristrami, Bouleng. Tr. Zool. Soc. xr. 1898, p. 6. 



Teeth in 3 or 4 series in both jaws, outer rather large. Deptli 

 of bodj' 2| to 2| in total length, length of head 2| to 3:| times. 

 Snout with straight upper pi-ofile, 1^ to 1| diameter of eye, 

 which is 3| to 4^ in length of head and 1 to 1^ in interorbital 

 width ; mouth moderate, f to | \\idth of head; maxillary extending 

 to below anterior border of eye ; 3 or 4 series of scales on the 

 cheek ; large scales on the opercle. Gill-rakers short, 8 to 10 on 

 lower part of anterior arch. Dorsal XIV-XV 10-13 ; last spine 

 longest, f to 1^ length of head ; middle soft rays produced in adult 

 specimens, about twice as long as last spine. Pectoral pointed, as 

 long as the head or a little shorter, not extending to origin of anal. 

 Tentra] produced in the adult, reaching vent or anal. Anal HI 

 7-9 ; third spine as long as or a httle shorter than longest dorsal, 

 soft rays produced like the dorsals. Caudal truncate. Caudal 

 peduncle as long as deep. Scales mostly cycloid, 30-32 yr^, ; lat. 1. 

 jjijg. Olive, with 6 to 8 more or less distinct darker bars, some- 

 times \yith a dark stripe along the middle of the side ; vertical 

 fins usually with more or less distinct lighter round spots ; a large 

 round blackish spot usually present between the anterior soft rays 

 of the dorsal ; a dark opercular spot. 



Total length 210 millim. 



Algerian Sahara to Lake Eudolf and the Lake of Galilee '. 



Chromis faidherbi, Eochebr. Bull. Soc. Philom. (7) iv. 1880, p. 167, 

 and Act. Soc. Linn. Bord. (4) vi. 1883, p. 134, pi. v. fig. 5, from 

 the Senegal, appears to be allied to C. zillii, but the description is 

 insufficient and contradicted bv the accompanying figure. 



D. XIV 11 ; A. Ill 7 ; Sq."27|. 3 dark bkrs on the body. 



22. TiiAPiA magdalenj:. 



Chromis magclaleiue, Lortet, Arch. Mus. Lyon, iii. 1883, p. 146, 

 pi. ix. fig. 2. 



* I have not seen Egyptian specimens : but, according to Panceri (Rend. Ace. 

 Sc, Soc. E. Nap. xii. 1873, p. 113), the species has been found in the artesian 

 wells of the oases of the Libyan Desert by Figari Bey (Stud. sc. sull' Eeitto, 

 1864, i. p. 287). J c J V 6 , 



